Virus Analysis: Tyrant

The most iconic, widely known, widely used, and most referenced virus in the entire series, the Tyrant Virus AKA t-Virus (sometimes capitalized) revolutionized modern warfare in the same fashion gunpowder did. While t-Veronica is technically a t-Virus, this analysis will focus on Umbrella's primary t-Virus developed at Arklay.


t-Virus Project

The secret main goal of the pharmaceutical corporation Umbrella was the secret production of living bioweapons called Bio Organic Weapons (B.O.W.s) using the capacity of the Progenitor Virus to rewrite genes. But Progenitor was far too lethal to establish itself in host bodies. The need for an artificial variant strain thousands of times weaker was apparent, both to produce B.O.W.s and to achieve the founders' ultimate goals of immortality and forced evolution. This was the aim of the t-Virus Project.

The t-Virus Project was the central focus of Umbrella, and had three stages conceptualized:

1. Creation of a new, ideal virus.
2. Stabilization of this virus.
3. B.O.W. production.

Any virus created from Progenitor as a part of this Project was given the moniker "t", or referred to as a "Clay Virus". While many t-Viruses were created under this project, the virus that accomplished all three stages would be officially called "the t-Virus". The completed t-Virus needed to be able to infect any host, and give animals traits ideal in a weapon (ferocity, vitality, and controllability). The ideal B.O.W. would be called the Tyrant, named after the Virus (a trend reused with the G-Virus).

In 1977, Umbrella Co-founder Dr. James Marcus created what would become the successful base for the finished t-Virus. This strain, unofficially dubbed t-Marcus, was created by injecting Progenitor into leeches. When a virus successfully establishes itself in a host, it mutates due to recombination with the host's cells. It not only changes the host, but is changed itself. The key to weakening Progenitor was to find hosts it could infect without killing, then extracting the recombinant strain from the host.
Leeches, like the Stairway to the Sun flower, were highly resistant to the damaging effects of the virus, allowing them to adapt and mutate.

t-Marcus was weak enough to infect other hosts, such as humans, accomplishing the first goal of the Project. While Marcus performed his own experiments with t-Marcus, Oswell Spencer (Umbrella's President and CEO) ordered Marcus' best students, Albert Wesker and William Birkin, to steal t-Marcus.
The duo were afterwards made the head researchers of the laboratory located under the Arklay Mansion, which became the primary t-Virus development facility.


Tasked with finishing T, Wesker and Birkin became fascinated with the Ebola Virus. What makes Ebola so dangerous is it's incubation period: a host will not display symptoms immediately, and will inadvertently spread the virus to others. This inspired the duo, as T was originally envisioned as merely a tool to create B.O.W.s, not a deadly weapon on it's own.
While the Zombie mutation of t-Marcus was not suitable for the Project's goals, it could outdo Ebola: instead of creating carriers who accidentally and indirectly spread the virus, T hosts would actively seek out others and infect them. As a precaution, T was modified to grow less infectious over time, to prevent a pandemic.
Wesker and Birkin sought out a sample of Ebola to incorporate into T.

t-Marcus was weakened and modified over the years by infecting a wide variety of hosts. By injecting t-Marcus into spiders (tarantulas), they created t/Clay Alpha. Alpha had greater results in arthropod hosts, and created the Webspinner B.O.W..
Alpha was also used with Great White Sharks to enhance it's abilities with marine life. While results were minimal, they were not in vain, and the Neptune B.O.W. was created.

After injecting Alpha into dogs (Dobermans), the Beta strain was created, as was the Cerberus B.O.W.. Beta had enhanced abilities in mammalian hosts, but humans still left much to be desired. Beta was further modified to create Beta II, which allowed for greater powers of genetic manipulation. bII created genetic hybrids such as the Hunter B.O.W..

While bII could produce favorable results in many organisms, the ideal B.O.W. Tyrant needed to be based on a human host for it to possess enough intelligence to effectively follow complex orders. However, the virus was too damaging in human brains, and could not create Tyrants in it's current state. Birkin refined the virus further, and managed to create a strain that could minimize brain damage in human hosts with a certain genome. But such hosts would be exceedingly rare. So rare, in fact, that Umbrella could not find such a host. The Project reached a standstill, and Birkin moved on with the G-Virus Project in a lab (called NEST) built beneath the nearby Raccoon City, while Wesker, feeling his limitations as a researcher, transferred to the Intelligence Division and plotted against Spencer and Umbrella.

T progress stagnated for years, until former USSR Colonel Sergei Vladimir sought employment at Umbrella. He passed the requirements for becoming a Tyrant, and rather than waste such a valuable find, Umbrella gave Sergei an executive position in exchange for ten clones of Sergei formerly created by the Soviets.
By incorporating the genome of these clones into the Virus, the Epsilon Strain was created, which could turn more hosts into Tyrants.

Two test subjects were used to create the first two Tyrants (the T-001 and T-002), and with the first Tyrants created Epsilon was officially made the Umbrella t-Virus. While Tyrants were costly and difficult to create from scratch, not to mention infertile, they could easily be mass produced via cloning.

Mansion Incident

During the administration of Epsilon into the host who became the T-002 in 1998, the Arklay Laboratory was attacked by the Queen Leech (a mutant with the memories of the deceased Dr. Marcus), resulting in Epsilon leaking as an airborne strain. While the researchers attempted to prevent a biohazard with protective suits, the virus reached the water supply. This led to the outbreak incident known as the "Mansion Incident".

Umbrella quarantined the Mansion and forced the staff within to study the effects of the virus as it spread. Any results were then recovered using the underground railway and used for B.O.W. development in other facilities. Birkin also used the railway to recover cloned B.O.W. embryos and virus samples, including a cloned embryo of the T-002, which became the base for the mass production model.

The outbreak went on for two months before the facility was eradicated by Rebecca Chambers from S.T.A.R.S. (Special Tactics And Rescue Service; a unit belonging to the Raccoon City Police Department, which had been lured to the Mansion by Wesker to collect combat data on the B.O.W.s and irregular mutants there) using the self-destruct system.
During the incident, the virus mutated and a new strain of Epsilon surfaced. This strain utilized a process called V-ACT to create Crimson Heads. The V-ACT strain was recovered by Birkin, who used it to create t-Birkin, which took V-ACT further and created Lickers. During these experiments, another mutant strain was discovered, t-Wesker, which restored the Progenitor ability to create super humans.

t-Birkin was mass produced by Umbrella, and sent to it's facilities all over the world for further developments. It caused multiple outbreaks, such as the Raccoon City Destruction Incident, the Sheena Island Incident, and the Spencer Rain Incident.
It was also used with the G-Virus to create t+G, and with t-Veronica to create t-02.
Another strain was created and leaked at Rockfort Island: t-Alfred. This strain could infect corpses. It afterwards contaminated the Umbrella Antarctic Lab.


Five years after it's creation, t-Birkin was refined further to create Perfected T, a strain which harnessed the full potential of the t-Virus. As such, it is likely it could infect corpses (like t-Alfred) and create super humans from adapters (like t-Wesker). Perfected T was stolen from the Umbrella Caucasus Facility (a massive facility built to mass produce B.O.W.s) in 2003 and leaked to the black market by Wesker, who defected from Umbrella some time prior. This resulted in the global age of bioterror, and Perfected T is now widely available to terrorist groups, corporations, and governments all over the planet. Umbrella itself was rendered defunct the same year due to it's involvement in B.O.W. production becoming public knowledge, although it was reestablished four years later under special conditions as a PMC called Blue Umbrella.

Perfected T was used during the Harvardville Outbreak in 2005, and in it's aftermath a vaccine developed by the Willpharma Corporation was recovered. This vaccine has rendered the direct use of Perfected T pointless. However, new strains have been developed by many different groups and new mutant strains are common. Rather than eliminate the problem, the vaccine complicated it by motivating bioterror groups to bypass the vaccine by continuing Umbrella's dark legacy. These groups include TRICELL, A-gua Industries, Neo-Umbrella, Shen Ya Pharmaceuticals, and even Blue Umbrella.

Most post Perfected T strains have only minor differences between them, but evolved strains have begun to eliminate necrosis and toxicity, resulting in smarter Zombie breeds and Tyrants created from simple injection. While many t-Viruses in the age of bioterror are not named, some are different enough to be given new titles. These include:
· t-Abyss
· t-Phobos
· t-Howard
· Kodoku
· A-Virus
As T is thousands of times weaker than Progenitor, and because it's mutations are tailored towards creating living weapons, it serves as the perfect base for new viruses.

Symptoms and Effects

The vast majority of T effects actually originate in Progenitor. Like eye growths with G, certain traits are simply more prominent in T. The trait that makes T different from any other weakened Progenitor strain is the Tyrant mutation, and all instances of this mutation come from T (for example, Ultimate Abyss, Morpheus, Diego, and Ustanak all get their traits from T). I cover the details of Tyrant creation and each type of Tyrant later.

T is actually an airborne strain naturally, but does not stay that way for long. It will quickly mutate into forms better suited to dispersal through water, saliva, blood, and even touch. After a sufficient amount of time has passed, it will become less and less virulent, until even Zombie bites will no longer spread it.
As late as 1998, 10% of hosts are immune to infection.

T has vastly different effects on different types of organisms, and this will be demonstrated as I cover each mutant animal. But certain effects are universal, such as:
· Increase in size
· Heightened aggression
· Increased vitality
· Lack of fear

The incubation period for the Virus varies wildly, and is affected by a number of factors. Namely:
· Environment
· Host resistance (being severely wounded affects this)
· Dosage
The strain of T used is also a factor. Epsilon could take many days before the onset of transformation, while Perfected T only took seconds.

I cover every known mutant created by the t-Virus in the following pages, in this order:
1. Zombies (Mammalian Hosts)
2. V-ACT Zombies (Crimson Heads, Lickers, etc.)
3. Tyrants
4. Arthropods (Spiders and Insects)
5. Annelids (Worms)
6. Reptiles, Fish, Amphibians, and Tunicate
7. Hybrids (Hunters, Chimeras, etc.)
8. Super Humans (Wesker, Mary Gray, etc.)
9. Miscellaneous (Undertakers, Nyx, etc.)


The most common byproduct of the t-Virus is the Zombie mutation. While commonly associated with T, this effect actually originates in Progenitor, and is a fairly universal symptom in all RE viruses. These creatures were named Zombies due to their resemblance to the Romero creatures in pop culture, hence why many characters call them as such despite not being aware of their official designation.

Zombies are the result of virus hosts being simultaneously weakened and strengthened, putting them in the middle ground between hosts who survive and die from infection. Necrosis (cell death) from the virus results in host bodies resembling walking corpses, and despite their sickly appearance the virus has also granted them vitality far exceeding natural animals. A recent source also claims they are capable of regeneration, although this may be limited to V-ACT or a specific strain of T.
Before Zombification, infected hosts undergo a number of symptoms:
· Intense Itching
· Fever
· Rash
· Increased appetite
· Psychosis
· Aggression
· Coma

Hosts will slowly lose their minds, and will be driven by hunger to attack and consume others (such as the infamous Keeper. "Itchy, tasty"). This symptom immediately precedes coma, and is short, but in the case of t-Phobos, this stage of infection lasts far longer before Zombification occurs (see Virus Analysis: t-Phobos).
During coma, the host will enter a state of suspended animation. Damage from the virus reaches a critical point, and vital signs drop so low they become undetectable. This gives the illusion Zombies rise from the dead, which is technically not true, as the brain never fully shuts down.
After a period, the virus strengthening reaches a critical point, and hosts regain consciousness as Zombies.

Zombies created from T are not as weak as Progenitor Zombies due to the weakened nature of T. Outward necrosis appears more severe, but it actually doesn't affect muscle strength. An increase in growth hormone causes Zombies to grow taller - the average Zombie height is 6 feet, 5 inches.
Zombie skin is most heavily damaged, turning pale and cracking. Exposed muscle is commonly seen as skin rots and peels. A common area to peel away is the skin surrounding the mouth, causing Zombies (and sometimes Tyrants) to lose their lips. The eyes become glazed over and turn a milky white, and any hindrance to vision is compensated with extra-sensitive hearing (which is used against them with the Zombie Jammer device).

Internal organs are heavily affected as well. The circulatory and respiratory systems are completely destroyed, making Zombies clinically dead. They no long breathe, allowing them to survive being buried or submerged in water (seen in RE3 and RE1, respectively). How they survive without oxygen is a mystery, although the Biology of Evil attributes it to leech genes in the virus.
The reproductive system is also destroyed, making all Zombies infertile.
Unlike other bodily systems, the digestive system is heavily strengthened to accommodate the intense hunger of Zombies. They begin to produce large amounts of highly corrosive stomach acid able to quickly break down flesh. They produce so much, in fact, that Zombies periodically vomit excess amounts from the body. They will attempt to direct this acid at prey, giving Zombies a valuable weapon against out of reach targets.

Zombie brains are devastated by necrosis, leaving much of the brain completely inactive. The parts of the brain still active will develop abnormally (sections of the thalamus, midbrain, limbic system, and hypothalamus) in order to compensate for the lost sections. Motor control is heavily affected, making Zombie movement slow, clumsy, and erratic (although some are capable of uncommon bursts of speed, such as the infected anatomist at Rockfort Island). All former personality and higher reasoning is wiped away entirely, as are most memories. Zombies often retain enough muscle memory to open doors, and commonly mill about places familiar to them as humans. Most Zombies are incapable of articulating speech, and will instead moan and growl. Advanced Zombies in modern times sometimes mutter simple phrases.

Zombie pain receptors are also inactive. Losing limbs, being shot, or being set on fire will not deter them. Instead, all they feel is hunger.
Zombies are in a constant state of starvation due to their metabolism being critically high. In order to support their oxygen deprived bodies, they must eat constantly. As infected flesh is stripped bare of nutrients, Zombies prefer to devour the flesh of uninfected hosts. As they grow more desperate, they will however resort to cannibalism. No Zombies beyond Crimson Heads are ever seen attacking each other, and they instead feed on dead or prone Zombies (the latter of which don't even seem to notice).
To conserve energy, Zombies will lie on the ground and play dead, biting the ankles of unsuspecting victims.
Due to their outstanding vitality, Zombies are impossible to kill unless the brain itself is destroyed/removed, or the body is totally incinerated. Zombies can also starve to death. A simple bullet to the brain is not always a guaranteed kill, as much of the brain is dead anyway. Destroying the brain stem is the safest and most reliable way to cease activity in a Zombie.

Zombie Variants

There is usually a great deal of consistency regarding how each individual Zombie will operate, but some alternate types have existed due to differences in how they were created:

Early strains of T could not revive corpses, but more advanced strains unlocked this ability. Undead Zombies are indistinguishable from living ones. These were encountered by Claire Redfield on Rockfort Island, when t-Alfred was carried by rainwater into shallow graves, causing the corpses there to reanimate.

Improved Zombies (aka Naked Zombies) were created at Arklay and NEST, which had even greater vitality. These were created via body strengthening surgery and primary injection of T.

During the Raccoon City destruction incident, Umbrella provided the RPD survivors with a special gas called P-Z, which was supposed to harm Zombies. Instead, this gas caused mutations in Zombies that heightened their combat abilities. It seems Umbrella either wanted to further compromise the survivors' safety, or they wanted to field test a new product despite the consequences. Poisonous Zombies created by P-Z constantly exhaled a purple gas that could poison prey. It seems the otherwise inactive lungs were repurposed to produce this gas. Some would expel a large poison cloud when the body was ruptured. Poisonous Zombies were distinguishable by their purple skin and glowing eyes.
It's possible this reaction is related to the Poison Ivy, which was also created by a t-Virus B.O.W. being exposed to a weaponized gas. This demonstrates the general adaptability of virus hosts.

Advanced Zombies have also been created by other strains of the Progenitor Virus, such as G, C, A, and Kodoku. The only Progenitor-based virus that hasn't been shown to create Zombie-like mutants is t-Veronica, although it's effects on corpses (if any) have yet to been seen.

Zombie Animals

The Zombie mutation is not limited to humans, and is actually common in mammalian hosts. These animals are considered Zombies due to severe necrosis giving them the appearance of undead creatures, and due to their ravenous appetite for uninfected flesh.

Dog - Virus activity in canine hosts is less lethal than in humans. Canine host brains are left intact, allowing infected dogs and wolves to hunt and run as they did prior to Zombification. Outward signs of decay are just as dramatic as in human hosts, but internal damage is limited. In REmake, dogs can be seen breathing.
Zombie Dog muscle mass is strengthened along with general vitality, although their bodies are not quite as resistant to damage as the larger Zombie humans. Their extreme aggression makes them very dangerous to humans and Zombies alike.
Dogs retain not only their hunting instincts after infection (like group tactics and ambush techniques), but training as well, making them controllable as B.O.W.s. This has made them desirable weapons even now, as they were used during the attack on TRICELL HQ. But their intense hunger must be maintained if control is to be asserted.
Canines created for use as B.O.W.s are called Cerberus (MA-39), named after the guardian of the gates to Hades in Greek mythology.

Ape - Marcus created B.O.W.s by injecting a pregnant Barbary Macaque ape with the t-Virus. It's offspring were called Eliminators due to their efficient ability to seek out and destroy targets. Like Zombie Dogs, Eliminators retained their intelligence and could be trained to follow orders. Their muscle mass increased until their skin ripped, and they were highly athletic. They even experienced an increase in intelligence.
They were effective, but were scrapped for further development due to their relative weakness. However, the Queen Leech created a small army of them, and the desperate Umbrella approved them for mass production many years later.

Rat - Zombie Rats were partly responsible for the incident at Raccoon City. They were lethal in swarms.

Bat - These include a wide variety of bat breeds, including herbivore fruit bats, which alter their diet after infection to become carnivores. Bats retain enough intelligence to fight in swarms, and sometimes retain a fear of open flames.
Two bats suffered a unique mutation and grew monstrous in size. Tyrant bats?
South American Fruit Bats encountered during Operation: Javier developed large growths on their heads.

Elephant - Oscar, a performing elephant at the Raccoon Zoo, became a Zombie and escaped confinement. Its diet became carnivorous, like infected bats, and it's heightened metabolism drove it to devour both humans and Zombies. It retained enough memory to be lured with music used during performances. Oscar's tusks developed abnormally due to mutation.

Hyenas and Lions at the Raccoon Zoo also became Zombies. They were similar to Zombie Dogs, in that they retained their muscular integrity and fine motor control even as their flesh rotted. Their ferocity and hunting abilities were greatly enhanced.
Many Zombie Hyenas were created, while only three Zombie Lions were present (two females and one male). The sole male Lion, originally named Max by the Zoo, was especially strong.

Besides mammals, birds also become Zombie-like after infection. Infected crows are the most commonly encountered in the series, although exotic Hornbill birds were also seen at the Racoon Zoo. Birds commonly become infected after eating the flesh of infected corpses. Necrosis is indeed present, but is undetectable due to feathers covering the body. The only discernable changes to appearance are in a small increase in size, and the development of red eyes. Infected bird behavior is unpredictable, and some flocks will only attack when provoked or disturbed while others are so desperate as to attack through windows. This may be dependent on how well fed the birds are.

V-ACT in Zombies

V-ACT (Virus Activation) is a process inherent to all viruses derived from Progenitor, including T. While commonly associated with Crimson Heads, V-ACT is responsible for most monster transformations after sustaining damage. When a mutant is severely wounded or even killed, the virus, which ceases activity after the initial transformation, resumes activity and infects the body a second time, causing further mutations. This may be caused by stress pathways which open in response to trauma that the virus uses to travel further. Creatures created by the G-Virus may practice V-ACT continually, while creatures created by the t-Virus can only undergo V-ACT once.
Initial Zombie mutations are minimal, as dead or damaged cells lack the energy to reproduce and alter form. However, during V-ACT, the increased virus activity causes extensive cellular repairs surpassing those from initial transformation. In a sense, Zombies can be "brought back to life" this way, causing further cellular changes in the process and altering their form.

Crimson Head

During the Mansion Incident, the Epsilon Strain mutated and harnessed V-ACT to turn damaged
Zombies into creatures called Crimson Heads, named for their red skin and the blood baths they create. The first encountered Crimson Head, the Crimson Head Prototype 1, was frozen and placed in a suspended coffin by the surviving researchers, who were unwilling to destroy it due to it's promise as a B.O.W.. After this strain was recovered by Birkin, Crimson Heads were studied and kept at the Caucasus Facility to be sold as products.
As V-ACT occurs in Zombie bodies, they enter suspended animation once again. Internal organs are repaired and the host circulatory and respiratory systems are restored. As a result, Crimson Heads very noticeably breathe, and their hearts pump blood. This blood becomes reoxygenated and turns a bright red. The skin remains damaged, and the now running blood seeps through the damaged skin cells, resulting in their red skin.
Extensive neurological repairs undoes prior brain damage, giving Crimson Heads more intelligence, and their motor control is restored, allowing them to run quickly.
Aside from repairs, Crimson Heads also mutate further, gaining several Tyrant traits. Muscle mass increases somewhat, and bone growth is promoted at the tips of fingers, creating claws. Crimson Heads are extremely deadly, and will kill other Zombies in their way as they pursue prey.
Forest Speyer, as a Zombie, displayed the ferocity and speed of a Crimson Head, but without the claws and red skin. It has been speculated he was attacked by both Zombies and infected Crows, based on bloody handprints leading to his location. This excessive damage during his initial transformation could have triggered premature V-ACT.
Javier Hidalgo performed primitive experiments on the Zombies he used as "guard dogs". He forced them into suspended animation, and as a result they underwent V-ACT and developed some Crimson Head traits.


After using the V-ACT strain of Epsilon to create t-Birkin, William Birkin created a more dramatic V-ACT mutation in damaged Zombies. After their bodies are repaired, t-Birkin Zombies will mutate into Lickers, named by the surviving Raccoon City Police for their elongated tongues.
Lickers undergo two stages of maturation. After V-ACT, Zombies awaken as Young Lickers, which will continue to develop into Adult Lickers. Like Crimson Heads, Lickers breathe.
The damaged skin of Young Lickers peels away, causing their smooth muscle tissue to become exposed. The brain, while it is repaired, swells in size. This gives them greater intelligence than Crimson Heads, but to make room for the brain, the upper section of the skull is destroyed, causing it to become exposed. Along with the skull, the already damaged eyes are completely destroyed, making Lickers blind. To compensate, the already considerably high hearing of Zombies is strengthened even further.
The skeletal system is completely mutated, forcing Lickers to become quadrupeds. Their heightened agility and sticky muscle tissue gives them incredible climbing abilities. The tongue is lengthened greatly, and Young Lickers control it with great dexterity, using it like a whip.

As Young Lickers develop into Adults, muscle mass increases greatly. This includes the tongue, which grows into a shape resembling a lance. Adult tongues are strong enough that they become piercing weapons rather than whips, and can ensnare or even decapitate humans.
Adult Lickers develop large bone claws far larger than those seen on Crimson Heads, which resemble talons. These have caused some Umbrella researchers to mistake them for "wild Tyrants". The similarities to Tyrants are simply due to the fact both were created with T.
Adult Licker teeth grow into sharp fangs.

Lickers are not only intelligent, but social. Young Lickers will stay together in a "nest", like the Apple Inn, and will venture out by themselves to hunt once they have matured into Adults.
Lickers are also intelligent enough to be trained to follow specific commands, issued with specific noises.

The Improved Zombies developed at NEST developed into Improved Lickers. Improved Lickers had a green surface that was more resistant to gunfire, and they had longer claws. These were also developed at Sheena Island.


V-ACT is a generally unpredictable process with varying effects. While most Epsilon Zombies become Crimson Heads, and most t-Birkin Zombies become Lickers, random mutations can result in alternate effects. Three unique examples are listed below:

One female Zombie in Raccoon City developed a unique mutation during V-ACT, and became the Suspended. This creature resided at the Apple Inn, and was protected by Young Lickers.
As it's name suggests, the Suspended hung upside down from it's legs. It had red skin and exposed intestines. It's tongue was especially long, and it's scream could attract more Lickers to aid it if it was in danger.

Some Zombies created from t-Birkin experienced a unique mutation and transformed into Pale Heads. Pale Heads were distinguishable in appearance by their pale white skin, which was heavily damaged and appeared to "melt" in spots. Pale Heads moved slightly faster than typical Zombies, and had the ability to quickly regenerate from most wounds. The only way to kill them was to inflict massive damage faster than they could regenerate.
Due to the name being similar to "Crimson Head", I'm going under the assumption that these hosts were the result of V-ACT, and due to random mutation became Pale Heads instead of Lickers.
Another possibility is that Pale Heads are actually G-Zombies. This is supported by their regenerative potential, and the fact they were first created at NEST. However, it was implied Pale Heads were the result of an unplanned mutation, while G-Zombies are the result of injecting G into corpses.
A third, almost impossible theory is that they are somehow related to the White Molded. They could simply be a reimagined form of Improved/Naked Zombies.

Some Zombies at the remains of the Umbrella Antarctic Lab also developed a unique V-ACT mutation. These creatures, simply called "Mutant Zombies", greatly resembled the Bloodshot created by the C-Virus Gas strain. They were immune to the Zombie Jammer produced by Blue Umbrella.

Other t-Virus mutants besides Zombies underwent V-ACT as well, but I'll cover them along with their original forms.


The primary purpose and main function of the t-Virus is to create "immortal soldiers" that are able to disguise themselves as humans. These B.O.W.s are Tyrants, named after the virus and for their extreme power and ferocity.
Tyrants are essentially enhanced Zombies, which have minimized necrosis and exhibit mutations artificially tailored to make them killing machines. These mutations include an increase in size and muscle mass, claw growths, unmatched speed and strength, and almost supernatural vitality. Tyrant intelligence is almost equal to human intelligence, but reduced enough to make them compliant. Their single-minded mentality to follow orders is comparable to a machine, and they will sometimes put themselves in harm's way to achieve a goal.

Most Tyrants lack the extensive physical decay of Zombies, although skin and eye damage is still present.
Tyrants are faster and more agile than any natural animal on the planet. Their hardened bodies can survive extreme damage like gunshot wounds or exposure to extreme elements, and they can heal from most non-fatal wounds (although they can be rendered unconscious).

While Tyrants are the intended effect of human infection with T, there are two problems which cause hosts to become Zombies instead:

1. Only 1 in 100 million hosts could originally resist brain damage.
2. Host bodies could not endure the drastic mutations, instead causing Necrosis.

The first issue was solved with the research gleaned from Sergei's clones. The second issue was solved by regulating the activity of the virus as it spread, and by putting hosts through extensive body strengthening surgeries. As only hosts strengthened in a lab could survive transformation, it was impossible to create Tyrants by injecting unaltered humans. Instead, Umbrella only created a handful of "new" Tyrants, and mass produced them via cloning.
Advanced strains of the virus, like t+G or Kodoku, could create Tyrants from simple injection, and did not require host augmentation.

All instances of Tyrant mutation come from viruses related to t-Epsilon. Uroboros, G, and t-Veronica can therefore not create Tyrants. Tyrants created with new viral strains are covered in my other Analyses.

T-001 and T-002

The first two Tyrants created by Umbrella were created with healthy young male prisoners. They were strengthened with surgeries, injected with Epsilon, and then placed in special capsules. These capsules were filled with a liquid that regulated how the virus spread in their bodies.

The first host became the T-001, also known as the Proto Tyrant. This host developed superior combat abilities, but suffered too much necrosis, giving it decayed flesh, an exposed spine, a serious twitch, and limited intelligence which hindered it's ability to follow orders. As a result, it was deemed a failure and sent to be disposed of, although it's unprecedented vitality allowed it to survive chemical disposal. It roamed the Water Treatment Plant and fought with Rebecca Chambers, Billy Coen, and Albert Wesker before being killed in the facility's self-destruct sequence.

The second host became the T-002. This Tyrant suffered the same mutations as the Proto Tyrant, but withstood necrosis and brain damage, making it a success. It was equipped with a device called a power limiter on the inside of it's body, which suppressed runaway mutation in order to keep it stable. This device might work by administering regular doses of antibodies to suppress excessive virus activity. If the limiter detected that the Tyrant's vital signs dropped too low, it would disengage, allowing the full potential of the virus to work in it's body to preserve it's life.
The T-002 was left alone in it's capsule due to the chaos of the Mansion Incident. Without training or mental programing, it began to reclaim it's free will, rendering it uncontrollable. When it was released, it exacted revenge by impaling one of it's creators, Albert Wesker, on it's giant claw. It then attacked the surviving members of S.T.A.R.S. in a blind rage, but was subdued and rendered unconscious. It's power limiter disengaged, and it became a "Super Tyrant". It's skin reddened due to increased blood flow and it's speed and agility increased greatly. It was soon after destroyed by a hit from a rocket launcher, instantly killing it before it could regenerate.

Both the T-001 and T-002 grew much larger, and developed a single giant claw (the claw of the T-001 was more deformed in shape, and resembled a trident. It developed very small claws on some of the fingers on it's other hand as well). In order to reduce aggression and keep them controllable, they were castrated to reduce testosterone. Their skin and eyes suffered some damage and lost color.
The Tyrants had exposed hearts. While heart expansion is a symptom of the virus, these appear to be secondary hearts grafted onto their bodies to support their expanded cardiovascular system. As these hearts are secondary, they are not vital enough to serve as a lethal weak point.

T-103 and Variants

Birkin recovered a cloned embryo of the T-002 and modified it further, creating the T-103. This Tyrant retained a more stable form, and was outfitted with an advanced power limiter during development which limited mutation enough to give it a human form. While it was smaller than the T-002, it's large size and damaged skin meant it's ability to disguise itself as a human was limited. It's power limiter was built into a special, explosion-resistant trench coat. As of the reimagining of RE2, the T-103 was also outfitted with a hat (to help disguise it) and an antenna-like device implanted into it's left temple. The exact purpose of this device is unknown, although it may have been used to relay orders directly into the brain (similar means of control were used with other variant Tyrant types at the same time).

When it's power limiter was removed, it, like the T-002, would develop into a Super Tyrant. This is actually it's default form.
The Super T-103 had large claws on both arms (except in one depiction, where it only has one), and even greater muscle mass. It's other abilities were also enhanced, although it became uncontrollable in this form. It also developed an exposed heart. In RE2make, the Super Tyrant's irises develop into reptilian slits, which is a trait inherited from Progenitor.

Many T-103s were cloned by Umbrella for use as body guards, soldiers, and assassins. Six were deployed to Raccoon City to kill the military team sent after Birkin and to recover the G-Virus sample in Sherry Birkin's pendent, and to kill any survivors along the way.
But before the Tyrant could be mass produced, combat data was required to work out any kinks.

A special variant clone of the T-103 was created to guard Sergei Vladimir. This custom model was called "Ivan". It was specifically modified to appear more human, and had a visor grafted on to it's face which featured a heads-up display that fed it orders. Ivan was faster and more intelligent than a standard T-103. A second Ivan was later created, called Ivan B. Both Ivans were slain by Albert Wesker.

After combat data was gathered from the Arklay Mansion from the fight between S.T.A.R.S. and the rampant T-002, further improvements were made to the T-103. Control and recovery ability was improved, and the updated model was mass produced at the plant on Sheena Island. Many of these T-103 (mass production type) B.O.W.s were evaded by Ark Thomson.
The Super Tyrant form of the mass production type lacked any exposed organs.

One mass production model (batch number T-078) was sent to Rockfort Island by a team led by HUNK for use as a training model for Umbrella paramilitary units. This Tyrant was deployed without a combat limiter, and had it's claws blunted. Despite this, it used it's strength to it's advantage and used it's arms like battering rams. After sustaining damage in a fight with Claire Redfield, it underwent V-ACT and grew new claws from it's right hand. It was destroyed after being launched from a plane by a missile.

Larger versions of the T-103 were later developed by an unknown group, and were deployed during the Eastern Slavic Republic's Civil War. These Tyrants were 5 meters tall, and were controlled by using a command program, perhaps like the antenna attached to the RE2make version of the T-103, or like the chip used with the T-0400TP (see directly below). Their coats were hardened with high pressure gas, while their power limiters injected their bodies with a static muscle relaxer. These only had one small claw in their Super Tyrant form.

Two variant T-103-based products were experimented on by Umbrella after it's mass production, which experimented with alternative methods of control:

T-0400TP - The T-0400TP or Tyrant R was created in the Raccoon above-ground laboratory. It's primary purpose was to exert control by downloading preset commands from an MO disk into a computer chip infused into the base of the skull. This method of control was presumably a more refined method than the one used for other Tyrants. It was a failure, as during deployment it was able to resist control when it overheard that it's life was in danger. It seems it's intellect was not reduced to make it compliant, as the researchers probably assumed the chip was enough to control it.
Other modifications resulted in it gaining even greater vitality. It survived multiple encounters with armed humans and Hunters, the explosion of it's neck bomb collar, and it's attempted absorption by Nyx, before it was defeated by Ada Wong and destroyed in the bombing of Raccoon City.
It's Super Tyrant form was referred to as "Tyrant Reborn", and in this stage it developed rock-like growths.

Nemesis-T Type - The Nemesis-T Type, also simply called Nemesis (Greek embodiment of vengeance, an apt name considering it's purpose to destroy S.T.A.R.S.) or the Pursuer, was created by injecting a T-103 with the Ne-alpha parasite (also called Nemesis). This B.O.W. was released in Raccoon City, but was destroyed by Jill Valentine and/or the bombing of the city. A second model was deployed at Rockfort Island to act as security. No further models were produced, as it's development was costly and it's appearance too far removed from humans.
The Nemesis parasite was an artificial organism created long before using the t-Virus. The Biology of Evil speculates it could have been a clump of cancer cells modified with the t-Virus and which contained genes from both parasites and human brains. After being injected into a host at the cellular level, the parasite works it's way to the spinal cord and attaches itself, bending the spine as it grows. It develops tentacles with sharp ends that worm their way throughout the body, feeding on t-Virus-infected cells from the host to sustain it's growth and life. These tentacles will emerge from certain points in the body, and can be used as weapons.
The tentacles secrete a liquid containing highly concentrated amounts of the t-Virus, which cause "cell activation" and aid in host regeneration. These secretions also make the tentacles a dangerous transmission vector for the virus. One tentacle will make it's way across the face and penetrate the front of the skull. From there it will destroy the frontal lobe of the host and enter the brain itself. It will hijack control of the body from there, taking over the host as a second brain. This eliminated the weakness of humanoid B.O.W.'s, the head, with the new brain protected inside the ribcage.
In short, the Nemesis Parasite is a parasitic brain that controls the host and enhances it's regenerative potential. The Nemesis brain is both highly intelligent and open to commands, and it's entire purpose as a B.O.W. is to control and enhance other B.O.W.s.
The invasive and destructive behavior of the parasite kills the vast majority of hosts, and the only known creatures strong enough to survive infection are Tyrants and Lisa Trevor. Even then, Tyrants infected with the parasite are torn apart by the growing tentacles, and must be stitched and stapled back together. The Nemesis secretions also cause the skin to become deformed.
The Pursuer sent to Raccoon was given a rocket launcher and a power limiter coat which helped suppress runaway parasite growth. It was capable of speech, but only repeated the name of it's targets: S.T.A.R.S.. It had superior comprehensive abilities, and expertly tracked and ambushed it's prey. It was also almost completely indestructible, surviving countless gun fights, explosions, and falls, in addition to being set on fire, electrocuted, bathed in acid, and even decapitated.
After sustaining enough damage and losing it's limiter, the parasite's tentacles expanded further as it mutated into it's second form. The heavy tentacles growing from it's arms rendered the use of firearms impossible, but were formidable weapons themselves. The parasite, attempting to adapt in response to excessive damage, grew in size and eroded both the central nervous system and the medulla oblongata. The Tyrant’s aggressiveness also increased.
After the destruction of the Tyrant’s original brain, the Tyrant host died and the parasite's survival instincts took priority (although it didn't forget it's orders). The parasite replenished biomass by consuming a slain T-103, and the dead host and living parasite merged into a form which functioned as a giant digestive organ, with the parasite and Tyrant cells competing for dominance. It became a quadruped to support it’s bulk, and it's ribs pointed outwards. It sprayed digestive fluids at it's prey from a bleb on it's swollen shoulder, which was actually an acidic pus containing toxins that it created in response to absorbing waste fluid.
After being blown to pieces by an experimental railway cannon, it still clung to life as a small shapeless blob before being gunned down and utterly destroyed with the city.
Here's an obscure yet disturbing piece of lore regarding the Nemesis-T Type:
"In addition, an interesting report was made about a "Nemesis-T Type" test subject in which this was transplanted into the latest Tyrant. In the case of the Nemesis culture process, it gained a sense of self and attempted to escape from the facility with others. That shows that the intelligence of the test subject drastically improved, and suggests a risk that a B.O.W. could become a new intelligent organism and rebel against humanity.
At that time, can mankind survive---?"

Alternate Tyrant Models

Some newer Tyrant models were created using new human hosts, and thus were not created from T-103 clones. These models represented the fierce internal competition at Umbrella once the Tyrant was created to outdo one another:

Thanatos - The Thanatos Tyrant (named after the Greek embodiment of death) was created by Umbrella scientist Greg Mueller at Raccoon University as a superior alternative to the mass production type. This Tyrant retained a more human form, although even with an internal limiter it still developed claws (albeit very small ones) and needed a secondary heart like the T-002. This heart was protected by a metal case. The vitality, speed, and overall combat abilities of Thanatos were greatly enhanced, and control seems to have been improved, meaning it gets to keep it's "member" (which is covered in stylish underwear) without fear of over-aggressiveness compromising control. It survived multiple firefights, electrocution, being crushed by the collapsing university, and being hit with two rockets, before it was killed by being injected with the Daylight Vaccine.
Like the T-0400TP, Thanatos' super Tyrant form was instead called "Thanatos Reborn". In this stage it's right arm grew in size and elasticity to compensate for the loss of it's left arm.

Hypnos-T Type - The Hypnos-T Type, or simply Hypnos, was developed at Sheena Island under the supervision of Island Commander Vincent Goldman. Hypnos was the closest and final attempt by Umbrella to create Tyrants that could be disguised as humans. It was created by introducing two special substances into gene culture: the Hypnos gene and a chemical called "Beta Hetero Nonserotonin".
Similar to the Kodoku Project, the Hypnos gene was discovered by pitting hundreds of thousands of cells against each other until only a single cell remained. This was to discover a gene that promoted genetic perfection for B.O.W. development. This experiment went on for three weeks, and the final cell showed itself as the researchers slept. As such, the genes extracted from this cell were called Hypnos, after the Greek embodiment of sleep.
Beta Hetero Nonserotonin could only be harvested from adolescent male brains. This chemical would secrete in response to adrenaline and noradrenaline, which regulate fear and extreme stress. In order to extract the vast amounts of the chemical needed to create the Hypnos-T Type, many young males were brought to Sheena Island, where their heads were cracked open without anesthetic. The traumatic nature of this operation generated large amounts of Beta Hetero Nonserotonin.
The Hypnos-T Type prototype had blue skin, green blood, and a single claw. It's height and size were equal to that of a normal human. As it was damaged it underwent two separate mutations, unlike most Tyrants. The first transformation could have been due to it disengaging a power limiter, and the second transformation could be due to V-ACT. In it's second form, it grew in size and developed fangs. In it's third form, it grew further, and became very animalistic, losing it's human appearance. It developed a stooped posture due to increased upper body mass, and it's heart expanded to the point it emerged from the body through a flap of skin. It was eventually destroyed by Ark Thompson using an attack helicopter. It's destruction along with the destruction of Sheena Island forced Umbrella to abandon it's goal of creating human-looking Tyrants.

Bandersnatch - The Bandersnatch B.O.W. was a prototype alternative to the Tyrant model. It was to abandon perfection as a weapon and a human form in favor of being a low-cost alternative. It was created by injecting a fertilized human ovum with T, and avoided the expensive maintenance and surgeries required for the T-103. As a result, it is deformed and far weaker. It's left arm failed to develop, with biomass instead shifted to the right arm. This arm was especially strong and elastic, like the Thanatos Reborn. It's face did not develop skin, and it's small legs made movement difficult. It used it's arm as a grappling hook, and could quickly transverse environments this way. It used it's arm to protect it's sensitive head, but could not attack, defend, or quickly move at once due to it's dependence on just one arm.
A group of cloned Bandersnatch were sent to Rockfort Island to collect combat data, and they were all destroyed there. However, the Rival Org used them as inspiration to create the Jabberwock S3.
The Bandersnatch was named after a creature with no discernable form from Through the Looking Glass and What Alice Found There.

T-A.L.O.S. - The Tyrant Armored Lethal Organic System, or T-A.L.O.S. was the most advanced Tyrant created by Umbrella. Talos was the name of a mythological bronze giant automaton that served as guardian of Crete. The development of T-A.L.O.S. actually began at the Arklay Lab, immediately following the success of the T-002. A third Tyrant was in development called the "T-A.L.O.S. body T-011", which would be controlled via computer chip. The outbreak halted further development, and the T-011 was recovered by Sergei and moved to the Caucasus Facility. While the T-0400TP continued the idea of using a computer chip to establish control, T-011 would be controlled not with preset commands, but live ones sent via a wireless connection to the chip.
Tyrant effectiveness against armored vehicles such as tanks and helicopters left much to be desired. As such, an evolved model that used heavy weapons and armor was envisioned with T-A.L.O.S.. While Tyrants performed best when unburdened by heavy equipment, it was decided cybernetic enhancements would ensure no combat prowess was lost. The recovered T-011 was modified over the course of just under five years, and was outfitted with a Synapse Connector, Cranial Unit, Sensory Unit, Circulatory Unit, Structural Unit, and a Control Unit. It was wirelessly connected to the Umbrella mainframe AI Red Queen, which controlled T-A.L.O.S. in real time. It was covered in an eight-piece set of white armor made from a special alloy that both protected the Tyrant without compromising mobility, and acted as a power limiter. It was given a special, oversized rocket launcher over it's shoulder. In order to support the launcher, one of it's arms was enlarged to balance the creature. Under the armor, significant biological enhancements were also present. It's skin was a unique dark shade, and it had glowing red eyes, like Progenitor sometimes does. It's spine was outfitted with cybernetics that enhanced it's nervous system.
Once it was completed, it was hoped the raw power of T-A.L.O.S. would bring Umbrella enough success to revive itself following it's financial troubles after Racoon. During a raid of the Caucasus Facility, Chris Redfield and Jill Valentine engaged the Tyrant in combat. By destroying the rockets before they ejected from the launcher, they destroyed it's armor and power limiter, resulting in mutation. The Super Tyrant form of T-A.L.O.S. was more severe than with other Tyrants. It lost it's lower body, and it's mutated spinal cord attached itself to the ceiling, hoisting T-A.L.O.S. above the ground. It sprouted tentacles which used the energy from it's cybernetic parts to create dangerous laser beams. It's other arm grew claws to match it's left one, and it's mouth split and tore into a vertical shape. As it's muscle mass increased, tears in the skin exposed vital organs which served as weak points, which Chris and Jill exploited to kill it.

Mutant Sergei - Before his final confrontation with Albert Wesker, Sergei Vladimir injected himself with the t-Virus. After a brief conversation with Wesker, he mutated into a Tyrant-like creature, and was afterwards destroyed. The virus he used was "enhanced". It could have been an experimental new strain, or simply the recently created Perfected T. If it was the latter, then that means Perfected T can create Tyrants from injection alone. Whether or not his transformation was timed or triggered through will is unknown, although the Umbrella Chronicles novelization implies the latter (in the book, it also gave Sergei powers prior to his final Tyrant transformation).
Sergei's mutant form had a Tyrant body, with a mouth gagged with a strange growth and arms conjoined into a single clawed tentacle. He developed some insect characteristics, strangely, such as insect limbs from his back and the ability to generate larvae. Sergei retained his intelligence following transformation due to his special resistance to T's brain damage symptom.
His grotesque and unique mutations seem to have been intented to reflect his tortured mindset, and Wesker used this experience to form a theory regarding the relationship between host mindset and mutation.
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Mutants by Phylum

The t-Virus affects different host types in different ways. This next section covers groups of monsters according to the phylum, class, or kingdom that the host species belongs to. As covered before, mammals and aves will transform into Zombies and Tyrants from T infection.


Arthropoda is a phylum of creatures featuring an exoskeleton, and includes insects, spiders, crustaceans, and centipedes. Arthropods make up 80% of all animals on Earth. Their simple biology and higher adaption to the virus made them promising and easy B.O.W.s to create in the early days of Umbrella, but their lack of intelligence and means of control eventually made Umbrella move on to more complex organisms.
The necrosis seen in Zombie hosts is not seen in arthropods, although they still experience heightened aggression, with omnivorous and herbivorous creatures becoming strictly carnivorous after infection. While intelligence is not damaged, it is also rarely enhanced. While Zombies and Tyrants are infertile, arthropod hosts tend to experience an increase in breeding capacity. This explosive increase in reproduction makes them a dangerous biohazard risk.
Physical mutation is usually limited, although all arthropods experience an extreme increase in size. While this symptom is common in all hosts, it is much more dramatic in arthropods. Size increases range not only from species to species, but from individual to individual. As they grow, many infected arthropods exuviate and shed their skin many times. While creatures with the body frame of insects should not be able to support such large sizes, virus activity causes strengthened muscle fibers to develop which not only support the enlarged hosts, but maintain their impressive mobility.
Many poisonous hosts like spiders and wasps experienced mutations making their toxins even more dangerous, and venom was capable of carrying and transmitting the virus.

Spider - Spider species were among the first creatures experimented on for B.O.W. development due to their incredible ability to adapt to any environment. The common name for B.O.W.s produced by infecting spiders is "Webspinner". Most spider hosts experimented on were tarantulas, and these early experiments helped stabilize the virus in arthropod hosts. Webspinners showed promising combat
abilities and adaptability, but did not satisfy all the requirements for B.O.W. production. Despite this, spider experiments continued with some satisfying results, and during it's financial troubles Umbrella seems to have approved them for mass production due to their presence at the Caucasus Facility. The fear aspect of fighting giant spiders and their simple means of production has caused their continued use by bioterrorists as late as at least 2010, when an American mall was attacked using many Webspinners.
The most common size for infected spiders to grow into is roughly the same as a human adult. During development, Webspinners commonly lose the ability to spin webs due to the necessary organs not growing in proportion to the rest of their bodies. Ironic, considering their name, but some spiders infected in the wild during outbreaks retained this ability.
Webspinners/Giant Spiders had considerable combat abilities. Their large fangs were sharp enough to harm human prey, and their venom was highly dangerous. This venom could be ejected as an airborn projectile, and it was strong enough damage prey without being injected by a bite.
Their speed and agility are intact, and they will ambush prey from different angles.
The abdomen of infected spiders could contain many offspring. Baby Spiders were the size of normal tarantulas, and could swarm their human prey after the death of their mother.
One Webspinner (or three, if all enemies in the Nightmare scenario of Umbrella Chronicles are to be believed) escaped after intended disposal at the Arklay Laboratory and made a nest under the courtyard in a large cavern. This specimen(s) continued to grow into a unique mutant called the Black Tiger, named after it's darker fur. It regained the ability to spin webs, and was two to three times the size of a typical Webspinner. It could have simply been a unique mutation, or perhaps it was an older specimen. If it's the latter, one has to wonder if Webspinners will ever stop growing if they aren't killed...
Umbrella created newer versions of the Webspinner from Black Widow hosts. Due to the change in species, their size was slightly smaller, but their venom even more lethal. Their lack of fur reveals that infected spider skin is heavily altered. The Widows no longer carried their iconic hour glass shape on the abdomen, and became a green and purple color. They may have experienced an increase in intelligence due to further enhancements.
In the Antarctic Base, one specimen grew much larger, and was essentially the Widow equivalent of the Black Tiger.
Special Webspinners were encountered during Operation: Javier called Jumping Maneaters. These specimens had considerable leaping abilities due to being based on South American Jumping Spiders. They were produced by Umbrella as cheap B.O.W. with an emphasis on effectiveness in humid environments.

Scorpion - The Stinger was a scorpion B.O.W. fought and killed aboard the Ecliptic Express that grew even larger than the Webspinner (at least 3 meters long, in fact). It's stinger failed to produce venom, although this could have been a design choice rather than a negative mutation. It's carapace was strong enough to deflect bullets. However, as it grew, it's carapace did not grow in proportion to it's body, leaving it's head exposed. It's claws were strong enough to cut steel. It was considered to mainly be a failure due to it's clumsy movements, weak head, and low intelligence.

Wasp - Wasps infected with T don't grow as large as some other arthropod hosts, although some individuals were far larger (possibly queens). Their size was still around three times as large, similar to their ancestors. Their smaller size was actually a boon, as they retained the ability of flight and were difficult to avoid. Their strengthened venom and tendency to fight in swarms made them deadly fighters, and their reproductive capabilities were explosive. They were one of the most dangerous transmitters of the virus.
During the Mansion Incident, a colony of infected Wasps (infected by feeding on infected plants) established a giant hive in the dormitory. Umbrella gathered combat data on them and used it to create the Halbert B.O.W. prototype. It was extremely large, and had the shell of a horseshoe crab, and the vitality of a cockroach, which may suggest Umbrella modified it with genes from other organisms. It was a queen, and could birth thousands of smaller offspring called "sentries", although the queen's attack power itself was limited. It was considered impractical as a weapon and sent to be disposed of, but it escaped and was eventually killed by Bruce McGivern.
During the Raccoon City Destruction Incident, infected flying insects resembling bees swarmed around the Rafflesia plant, and went into a frenzy when it was destroyed.

Cockroaches - During the Raccoon City Destruction Incident, the roaches in the sewers became infected and grew in size and ferocity. While they did not grow much, like Wasps, their breeding capacity was unmatched. They entered a turf war with the infected rats, and won due to their numbers (being Zombies, the rats likely could not reproduce).
Roach swarms could cover areas like a blanket, and they went for the jugular when attacking humans.

Moth - Moths were experimented on by Umbrella on two known separate occasions, and each with a different species leading to unique mutations. Several specimens were created at the NEST facility using Gypsy Moths. These became monstrous in size, but their wings were not large enough to support their weight, limiting their flying abilities. Their phosphorous powder was much more toxic, and they were strong enough to carry an adult human. They developed a nest during the outbreak in a hallway which housed many larvae. The number of adults were small when compared to the number of eggs and larvae, as the success rate for emergence and development was lessened after their enlargement. More of these moths were created through secondary infection at Sheena Island, and a nest was located under the prison.
At the Antarctic Lab, separate experiments took place with Moon Moths. These did not grow quite as large as the specimens at NEST and Sheena Island, but retained the ability of flight. They dropped highly poisonous phosphorous clouds over prey. The Antarctic Moths also developed a large nest in a hallway after escaping confinement. This nest had human corpses attached to it's walls and ceiling to house their young. These young moths were parasitic in nature, and would burrow into bodies, living or dead. The young moths, when developed enough, could burst from corpses or even active Zombies to attack potential threats.

Centipede - A centipede host transformed into the Centurion (name for Roman commanders) at the Executive Training Facility, and was killed by Billy Coen. The Centurion was much larger than a human (over ten meters long), and could carry prey as it moved using it's many legs.

Earwig - The European Earwig beetle was a popular pet in Raccoon City. Some became infected during the outbreak, grew to a massive size, and resided both in the city and the surrounding woods. They were called Scissor Tails due to their scissor-like mandibles that were used as effective weapons. Due to a mutation, they gained the ability to produce poisonous venom. Their wings failed to grow in size, and they crawled very slowly on the ground.

Flea - Infected fleas, called Mega Bites, infested the Racoon Subway System. They grew in size and attacked prey in pursuit of blood, becoming predatory rather than parasites. When they consumed blood, they expanded and turned red. Mega Bites retained their high jumping abilities.
They developed a society centered around a queen, the Giga Bite, which was larger in size.

A unique Arthropod mutant appeared during the Raccoon Incident, called the Drain Deimos (DD). The original host species is impossible to determine, although it appears to have been a flea-like parasite originally. It grew many times it's original size and like the Stinger it's exoskeleton did not grow in perfect proportion to it's body, resulting in exposed muscle tissue. It mutated heavily and developed a unique shape, with clawed appendages allowing it to scale surfaces. While it was primarily a crawling creature, it could stand on it's hind legs before striking. DD were asexual creatures that reproduced through monogamous reproduction. DD offspring were parasitic leaping creatures that became predatory when they grew.
Deimos was the Greek personification of Dread, and the DD was given the name due to it's grotesque appearance. The Drain part of it's name is in reference to it's main method of attack and seeking nourishment: the DD uses it's fangs to penetrate the spine of prey and drain them of cerebrospinal fluid.


Annelida is a phylum consisting of many kinds of worm species, such as Earthworms and Leeches. The Virus seems to affect annelids in much the same way it affects arthropods, with an increase in size and reproductive capacity being the most notable mutations.

Earthworm - Umbrella's Incineration Disposal Plant in Raccoon City, prior to the outbreak, could not keep up with the infected waste being sent there, resulting in contamination failures. Some worms fed on waste (disposed test subjects) and became infected with the t-Virus. They grew to an enormous size, approximately 10 meters long, and created a vast tunnel network under the city. Two known adult specimens were encountered by Jill Valentine, although one was younger with softer skin due to recently shedding. The other specimen was found feeding on corpses at the cemetery, and was killed by Jill.
The second specimen's behavior earned it it's title from Umbrella: Gravedigger. Gravediggers were extremely strong and resistant. They were talented diggers, and had four large mandibles capable of clawing through concrete. Inside their mouths were many rows of sharp teeth. Their size and impressive digestive system allowed them to consume adult human bodies whole.
Gravediggers produced offspring called Sliding Worms, which took around two hours to hatch from eggs and could grow into adult Gravediggers in a week. Sliding Worms lived in damp areas, and developed leech-like behavior. They would attach themselves to prey with their sharp mandibles and quickly drain
them of blood. Fed Sliding Worms then expanded and turned red due to being filled with blood, like the Mega Bite. Sliding Worms were around the size of a typical snake, and were named for the way they moved on the ground.
Umbrella gathered combat data on the Gravedigger, which showed promise as a weapon. By modifying the genes of an earthworm and injecting it with the t-Virus, the Gulp Worm B.O.W. was created. The Gulp Worm was smaller than the Gravedigger, but still large enough to devour and digest humans. It was designed with the idea of infiltrating enemy territory undetected then launching surprise attacks from below. In Darkside Chronicles, it is suggested it was smart enough to be trained. It's sense of smell was powerful enough to accurately detect prey while underground.
The Gulp Worm was sent to Rockfort Island for training it's paramilitary and testing the Worm's combat abilities. There it fought Claire Redfield, killed Rodrigo, and was finally destroyed by Chris Redfield.

Leech - Leeches were capable of not only surviving infection with Progenitor itself, but turned into evolved organisms with advanced intelligence, social skills, and mimicry abilities (see Virus Analysis: Progenitor). Leeches infected with the t-Virus were not as advanced, however, due to the weaker nature of T or the fact the Progenitor Leeches created by Marcus were allowed to mutate and evolve over the course of ten to twenty years, while the known T leeches were only active several days to a week.
An aquatic leech beneath the Raccoon Hospital grew immensely and gave birth to many offspring. These leeches were social creatures with a single queen, like with the Marcus Leeches. The offspring of this Giant Leech invaded the hospital in search of blood.
These Leech offspring were slightly larger and more ferocious, but lacked the ability to mimic prey. Instead, they developed the ability to control a human corpse when a large amount of them attached themselves to a body. This curious organism was the Leech Man. The Leech man could be killed if the leeches covering it were destroyed by an intense heat, but it was otherwise extremely resilient. It's body could be manipulated with great dexterity, and it could quickly transverse the hospital by crawling through air vents. It was fairly unintelligent, however, and was easily distracted by the scent of blood, which it greedily consumed from it's prey and discarded blood packets. The unique nature of these Leeches is due to the tendency of leech hosts to adapt in response to the virus and gain entirely new traits not seen in natural organisms.


All of the following creatures belong to the Chordata Phylum, and most are Vertebrata. Mammals are chordates as well, although they transform into Zombies instead. While there are significant differences in each of the following creatures, all display very similar mutations (rarer size increases, rise in aggression and vitality). Their mutations are less dramatic than arthropod and annelid hosts, and show less practicality than mammalian hosts. These will be split into each class they belong to:


Reptilian hosts of the t-Virus display very minor mutations. They, like arthropods, suffer no necrosis, but an increase in size is less common. Some reptile hosts are largely indistinguishable from their uninfected counterparts, with the main difference being an increase in aggression.

Snake - Snake hosts usually seemed to lack amplified combat abilities, and were merely more aggressive. Adders infected with the t-Virus developed more potent venom, and a pink variety had an especially lethal bite. They would drop from trees to ambush prey, and would pursue targets on land and in water. Their appearance was unaltered, and they were no stronger than uninfected hosts. The only other improvement was in reproduction, making their numbers swell. They were nonetheless dangerous.
At the Arklay Mansion, a cottonmouth snake specifically bred to be used as a test subject escaped and became infected with the t-Virus. This snake experienced far more dramatic mutations, and was named Yawn after the way it opened it's mouth before striking. It experienced a massive increase in size, although it's length was not proportionate to it's width. Along it's body developed misshapen growths.
It used it's unmatched dexterity and fast speed to slither through cracks and crawlspaces in the mansion, expertly picking off researchers with it's massive fangs and powerful jaws. It's primary nesting/hunting grounds were the attic and library. If it's prey somehow survived, they would be killed by it's powerful venom, which was resistant to Blue Herbs and strong enough to kill an adult human in minutes.
Yawn retained it's hunting instincts, as it knew how to expertly stalk and corner prey, and knew when to flee. It was also either extremely resilient, or could rapidly heal from wounds, as it survived multiple encounters with both S.T.A.R.S. Alpha and Bravo team before it was finally slain.
Yawn's superior mutations could have been due to a variety of factors:
1. The species of snake used may be more adaptable to the virus than adders.
2. The host was bred for experiments, and so, like the Gulp Worm, may have been genetically modified to react this way to the virus.
3. It could be a freak mutation, or the result of environmental factors.

Crocodile - Crocodiles at the Raccoon Zoo became infected with the t-Virus, and were called Gnaw. While they were far more aggressive, they were otherwise seemingly unaffected aside from a small increase in size and agility.

Alligator - Unlike crocodiles, infected Alligators grew dramatically in size. They were large enough to devour prey whole, and preferred damp environments like sewers. Pet alligators infected with T were encountered in the sewers of Raccoon City and Sheena Island.


Fish, like reptiles, are barely affected by the t-Virus, and by most Progenitor-based viruses for that matter. The lack of improvements along with dependence on aquatic environments and lack of control makes them largely unsuitable for B.O.W. production. Human/Fish gene crossing also seems to be difficult. However, some impressive mutations are still present, showcasing the ability of the virus to adapt in all forms of life. Successful marine B.O.W.s and aquatic chimeras were eventually created with t-Abyss (see Virus Analysis: t-Abyss).

Shark - Umbrella constructed a large aquarium called the Aqua Ring underneath the dormitory of the Arklay Mansion, where they performed experiments on Great White Sharks. These experiments
stabilized the Alpha strain of the virus in fish hosts. During the outbreak, a crazed researcher destroyed the glass of the Aqua Ring, flooding the area and setting the sharks loose. Later, in Raccoon City, Bull Sharks kept at the Raccoon University became infected with T as well (with one growing into a size comparable to a Megalodon). Any shark species transformed by the t-Virus was called Neptune (FI-03), after the god of the sea.
While Great White Sharks die in captivity, an increase in vitality allowed Neptunes to survive. Even when all the water of the Aqua Ring was drained, the Neptunes within still survived, although they were immobile. The initial Neptune was pregnant when she was infected with the t-Virus, causing her offspring to be born as Neptunes, like the Eliminator. This piqued the interest of Umbrella, who eventually wanted B.O.W.s that were capable of reproduction to replace mass production via cloning (a concept which was realized with the G-Virus). Only two Neptune pups survived the mutations caused during development, and were smaller than their mother due to their younger age. They were also much weaker. The Mama Neptune grew even larger than the massive host species, and was the perfect killing machine underwater. She was so aggressive that she would ram into the glass containing her, and could devour humans whole. Her vitality was also impressive, and was only killed after being exposed to a massive, prolonged dose of electricity.
Despite these improvements, the fact Neptunes developed no increase in intelligence and were immobile on land made them impractical B.O.W.s. However, they were later developed at the Caucasus Facility, so either the desperate Umbrella cloned them for mass production anyway, or they decided to continue experiments.

Piranha - Javier Hidalgo infected pet piranhas with the t-Virus at his compound and used them to execute traitors. When he flooded the nearby village in his hysteria, he released the Piranhas into the river, which turned the populace into Zombies.
Infected Piranhas grew in size, and in their aggression would actually pursue prey on land, like the Ghiozzo. Their heightened vitality allowed them also to survive outside of water for a limited time.
While piranha ferocity is greatly exaggerated in movies, infected piranhas had comparable behavior to their fictional counterparts. In swarms, they would quickly devour entire humans in a very short amount of time. While they weren't the most practical weapons, they were great instruments of terror.


Amphibian hosts showed more promise than fish for marine B.O.W. production due to their ability to survive on land. While they increased in size, ferocity, and vitality, they also suffered a general ocular degeneration, like Zombies and Lickers, harming their eyesight. They also were unintelligent and reliant on moist environments.

Frog - Frog hosts, called Lurkers, grew considerably, and were large enough to devour large prey. Their digestive system was highly advanced, and could digest a whole adult human. Their tongue grew in strength, and was strong enough to drag prey into it's gaping mouth. It retained it's swimming and leaping abilities. Despite these improvements, it's low intelligence made it undesirable as a weapon, and it's effectiveness in combat was outdone by the Hunter Gamma. It's eyes completely atrophied, forcing it to rely on it's other, enhanced senses. A new ear developed where it's eyes used to be.
Lurkers were first created by Marcus as early B.O.W.s, were recreated by the Queen Leech, and created in the sewers of Raccoon City through secondary infection (at least, in The Darkside Chronicles).

Salamander - Salamanders were experimented on at the lab inside the Training Facility at Rockfort Island. These experimental B.O.W.s were called Albinoids. Albinoids failed to develop pronounced facial features, making them appear to be headless. This could be related to the atrophy seen with Lurkers. Infant Albinoids were small and larvae-like, and would completely mature over the course of mere hours into human-sized adults.
Most noticeably, adult Albinoids gained the ability of bioelectrogenesis, a trait seen in creatures such as Electric Eels, but not salamanders. This trait was probably the result of:
1. An evolutionary new trait brought about by the virus. Progenitor created both Salamanders and electric eels, so T developing a trait from one in another is entirely plausible.
2. A random mutation.
3. Genetic modifications by Umbrella, possibly involving splicing in foreign genes.
While in water, an adult Albinoid could discharge an electrical current strong enough to kill prey. This B.O.W. was designed to be covertly deployed into enemy territory as an infant, which would sneak into the water supply and electrocute any prey who came into contact with the water.
However, all but one known specimens were destroyed at Rockfort by the Island's self-destruct sequence, and the only survivor was killed by Chris Redfield.


Tunicates are marine invertebrate, and are a sister group to fish. The only known Tunicate mutant created by the t-Virus was the Nautilus (named after a mollusk, and coming from the Greek word for "sailor"), which was based on sea squirts. The only other Tunicate B.O.W. seen in the series was the t-Abyss-created Draghignazzo. Due to mismanagement by Morpheus Duvall at the Umbrella Disposal Facility he was charged with, many failed B.O.W.s escaped confinement, including at least two Nautilus creatures, which mutated further in the wild. These grew to a massive size, and were observed by researchers. The Nautilus was immobile and lacked offensive capabilities, but produced offspring that would shoot through the water at targets. The researchers named these offspring Torpedo Kids due to their strange behavior. Torpedo Kids appear to have human faces, which may be due to recombination with previous human hosts whose genes were left inside the virus, like the Brain Sucker, or due to Umbrella's modifications. The bodies of Torpedo Kids were extremely fragile, but were filled with highly corrosive acid. When charging into targets, Torpedo Kid bodies burst, spraying acid all over the target. This suicidal behavior was probably displayed in order to protect the mother Nautilus, similar to how eusocial insects will defend their queen and hive/nest at any cost.


Plants infected with the t-Virus experience extremely dramatic mutations, and will amazingly develop animal attributes like locomotion and intelligence. These unbelievable results are due to Progenitor being more compatible with some species of plant hosts, like the Stairway to the Sun Flower or the monstrous plant encountered by George Trevor. The development of animal traits is due to Progenitor creating those traits in the first animals in the first place.

Monster Plant - Most generic plant species become Monster Plants, which vary in appearance. They always experience an increase in size. The most common form for Monster Plants to take is that of a strong, vine-like tentacle. These tentacles are seen sprouting amongst regular plants, and so it is impossible to tell whether or not they are attached to a larger body. They are covered in a hardened skin which nullifies shock, making them highly resistant to damage.
The tentacles will lay dormant until they sense movement, at which point they spring to life and either whip or grab nearby targets. As they appear to lack any means of obtaining nutrition from targets, this seems to be purely defensive behavior. Such tentacles were found growing at the Arklay Mansion, the green house of the Raccoon Zoo, and in the Arklay Forest.
Other plants simply grow and grow, and do not seem to display violent behavior. One such plant grew inside NEST (replaced with Plant 43 in RE2make).
The greatest threat posed by Monster Plants is the infected pollen they carry, making them extremely dangerous transmission vectors for insects and other plant life.

Plant 42 - During the Mansion Incident, an insectivore plant in Observation Room 42 at the dormatory of the mansion became infected by the t-Virus. This plant mutated and was observed by the surviving researchers, in particular Henry Sarton, who named it Plant 42 after it's location. This plant was eventually destroyed by S.T.A.R.S..
Plant 42 developed many predatory traits due to being based on an insectivore. It had two main sources of nutrition - water and blood. It's main body was a giant bulb suspended from the ceiling, and it's roots descended into the Aqua Ring below and fed on the water there. This water was contaminated by a variety of chemicals, and it was theorized that these chemicals contributed to it's growth.
While the main body of Plant 42 was immobile, it developed many tentacles like those seen in Monster Plants. These long tentacles spread throughout the dormitory through cracks and ventilation shafts, seeking humans to catch. The tentacles developed suction organs which quickly drained blood from prey. Other tentacles produced acidic sap.
The tissue of Plant 42 was resistant to gunfire, and even the destruction of it's roots using the chemical V-JOLT was not enough to kill it. However, it's main body housed a vulnerable organ, and it was vulnerable to fire. Plant 42 actively sought to defend it's body, and it would purposefully use it tentacles to block off routes of escape. This behavior, combined with it's hunting skills, showcases the most amazing development in Plant 42: intelligence.

Ivy - Umbrella never considered using plants as a base in B.O.W. development until after the results shown in Plant 42 revealed such B.O.W.s could have potential. The data collected from Arklay involving Plant 42 was used to develop a B.O.W. called Plant 43, or as it's more commonly known, Ivy. Ivy were also based on insectivore plants, which were selectively bred before injection of the t-Virus.
Ivy were modified to develop a roughly human shape, with limbs formed from modified tentacles. It's "legs" moved it's body at a slow pace by using the movement of liquids contained in the tentacles. It's "arms" were tipped with buds that resembled ivy, hence their name. The "mouth" resembled a blooming flower, and contained a stamen and pistil they could use to reproduce using seeds. It developed intelligence, but not enough to train and control it.
Ivy, like Plant 42, sought nutrients from both water and blood. They had highly absorbent exterior tissue which absorbed water vapor, while they attacked human and animal prey to drain them of blood. The main method of attack was through both their whip-like tentacles and a deadly digestive enzyme they could spray over a short distance, like the acidic sap used by Plant 42. Ivy's unique biology and tough plant tissue made it difficult to kill, although it retained a weakness to fire.
The absorbent skin of Ivy made them vulnerable to airborne toxins. However, they were capable of adapting to many kinds of toxins and becoming stronger. In the case of the P-Epsilon anti-B.O.W. gas, they absorbed the gas and became Poison Ivy. As their name suggests, Poison Ivy could expel a poisonous gas at targets. Whether or not this gas is directly related to P-Epsilon is unknown. Poison Ivy develop a red and purple color, in contrast to the green and orange colors of the regular Ivy.
Both types of Ivy were encountered at NEST (or not) and at the Tyrant Plant at Sheena Island. While their slow movement, weakness to fire, and low intelligence left much to be desired as a weapon, Ivy resilience to damage, reproductive abilities and likely low maintenance led to their mass production at the Caucasus Facility anyway.

Umbrella continued Ivy experiments in an effort to increase their effectiveness. While it's weakness to fire could not be removed, enhancements focusing on speed were attempted. An alternate plant species was used to create an Ivy, then it was modified by introducing human genes, creating the Ivy +YX. This new species of Ivy had enhanced endurance, offensive abilities, and mobility. It could not survive outside warm environments due to the tropical plant used as a base. This led to it's mass production being shelved, hence why only regular Ivy are encountered at the Caucasus Facility. Nonetheless, several prototype Ivy +YX were purchased by Javier Hidalgo. The Ivy +YX was named after human chromosomes. It developed very human-like legs, making it's movements much faster.

In the 2019 reimagining of RE2, the nature and origin of the Ivy creature was significantly altered. In this version of the story, "Plant 43" and "Ivy" are two separate creatures. Whether or not these creatures replace the original Ivy in the lore is unknown, although three possibilities exist:
1. The 2019 iteration of Ivy is non canon.
2. The original Ivy, Poison Ivy, and Ivy+xy have been retconned.
3. Plant 43, Ivy, and Ivy Zombies (2019 version) are three different creatures that simultaneously exist in the same universe. If the classic Ivy was not developed at NEST, it may have been created at Sheena Island instead, explaining their presence there. The classic Ivy could even be based on data obtained from the Ivy Zombie.

Plant 43 - Using the data obtained from Arklay on Plant 42, the researchers in the eastern section of NEST developed a similar plant creature with the t-Virus called Plant 43. This specimen was also gigantic in size, and could use tentacles to feed on human prey. The main body of Plant 43 is never seen.
During the invasion of NEST by the USS and the subsequent outbreak, the researchers in the eastern section were cut off and trapped. Amidst the chaos, maintenance on Plant 43 was neglected, and it grew until it's vines invaded the entire area, similar to Plant 42. The researchers became prey to the plant,
and were used to fuel it's growth. Eventually, Plant 43 went dormant again, perhaps due to being well fed and to conserve energy. It was eventually destroyed or weakened by P-Epsilon gas.

Ivy Zombie - The "Ivy" or "Ivy Zombie" was a type of creature created by Plant 43 using human corpses. Plant 43 was capable of implanting seedlings into corpses, which used their developing roots to drain the body of nutrients. Once the seedlings developed, they would control the remaining corpse in a matter similar to the Leech Man. The resulting Ivy would attempt to feed it's attached plants by attacking and devouring human prey. Plant 43 likely used these Ivy to protect itself while it was dormant, like a colony of insects protecting a queen.
The remaining flesh of the Ivy Zombie is mutated to suit the needs of the plant parasites. Most notably, the mouth develops sharp teeth and jaws strong enough to crush an adult human head instantly.
Vine-like tentacle growths were wrapped around the Ivy's body, either reinforcing the drained corpse or acting as the means of control, like strings on a marionette. The body of the plants themselves manifested as brightly colored buds emerging at various points. Ivy Zombies are even more resilient than both Zombies and the original Ivys. The plant parasites act as the source of the creature's activity, and must be destroyed in order to stop it. Even if all of it's bulbs are destroyed, the Ivy will only be incapacitated as the plants quickly repair themselves. The only way to completely kill the creature is to completely incinerate the entire body.

Rafflesia - The Rafflesia is a genus of natural plants named after Sir Starnford Raffles. It is a holoparasite with no leaves, stem, or roots. The only part visible above ground is a large flower, while underneath it is comprised of vines. It is the state flower of Indonesia, and is capable of horizontal gene transfer.
Rafflesia are Carrion Flowers ("corpse flowers") due to their resemblance to rotting flesh and the stench they create when they bloom.
While Rafflesia are native to southeast Asia, one Rafflesia arnoldii was featured at the Raccoon City Zoo for display. The arnoldii is the largest known single flower on the planet, and is rare due to the fact it takes months to bud, yet only lasts for several days and requires a close proximity to others of the opposite gender to reproduce.
During the Raccoon City Destruction Incident, the flower coincidentally bloomed, and it's fowl stench attracted many t-Virus infected insects, which led to the infection of the flower itself. It's only known symptom was that it became a carrier of the Virus, and when a group of survivors destroyed it, the swarm of infected insects surrounding it went into a frenzy.

Green Zombie - Infected organisms are highly adaptive, and develop an artificial ecosystem inhospitable to humans. The Green Zombie is one example, and is the result of infected plants growing on the surface of Zombie skin. The Zombie remains active as the plant roots gather nutrients from it's body. One such species of plant began to produce poison, which harms those who come into contact with the Zombie, making killing prey easier for the Zombie. These deadly symbiotes hunted in the forest near Raccoon City.

Dorothy - Dorothy Lester was the wife of Albert Lester, the administrator of a hospital located in the Arklay Forest. Al was in collusion with Umbrella, and used the hospital patients as test subjects for the
experimental t-Virus strain called T-JCCC203. This virus strain was created under the t-Virus project, and was meant to cure deadly disease. It is unknown if T-JCCC203 was directly related to the main t-Virus developed by Marcus, Birkin and Wesker.
While T-JCCC203 successfully cured disease, it eventually turned hosts into Zombies. Dorothy became terminally ill and was cured with T-JCCC203, but her condition worsened and she became a Zombie, starting an outbreak throughout the hospital. Umbrella scraped the project and covered the incident up, and the hospital was abandoned. Dorothy's corpse was left behind, which came into contact with a nearby plant and spread T-JCCC203 to it. This plant grew around the corpse, and became a giant mutant.
Al Lester returned to the hospital regularly, and five years after the incident discovered the mutant plant in the basement. He identified it as the reincarnation of his dead wife, and thus called it "Dorothy".
Throughout the year, Al fed "Dorothy" humans and animals, Little Shop of Horrors style. During the Destruction Incident of Racoon City, survivors from the city encountered Dorothy, and after poisoning it's roots destroyed it's body, releasing the corpse of Dorothy in the process.
While animal/plant hybrids exist in this series, the "Dorothy" plant did not appear to be physically connected to the real Dorothy. It may have inherited human traits from the virus in her body, however.
As the "Dorothy" Plant displayed predatory behavior, it, like Plant 42 and Ivy, may have been based on an insectivore plant. While it's main body was located in the basement, it's roots and tentacles spread throughout the hospital, to a degree greater than Plant 42. This is likely due to how long the plant was active. It's mass was so entwined with the architecture that it's destruction led to the collapse of the building. It may have been responsible for the creation of the Green Zombie. It had tentacles like those seen with Monster Plants. Rather than suck blood, it appears it devoured entire bodies using a large mouth on the main body.

The nature of and relationship between Plant 43 and the Ivy Zombie is incredibly similar to that of Dorothy and Green Zombies. This demonstrates a mutation tendency in plants infected with the t-Virus.

Evil Shade - An unidentified plant species became infected and grew on the roof of the "Dorothy" hospital. These plants, called Evil Shades, had bulbs which produced a deadly poison mist.

Genetic Hybrids

Besides mutating natural organisms, the t-Virus is also capable of creating cross-species chimeras (not specifically the creature Chimera - for clarification, I will henceforth use the word "hybrid"). As the virus can infect and alter the genes of any organism, it is possible for virions to transfer genetic material from one host to another. As the virus assimilates cells, the genetic coding of the cell is rewritten using the virus' own genome. This means traits from one animal can be replicated in another species. Without the Progenitor Virus' capacity to remake life, such modifications are normally impossible.
As demonstrated in previous sections of this analysis, most T B.O.W.s do not display all of the desired traits in a practical weapon, at least until the Tyrant was created. Different hosts gain different advantages and disadvantages. But by using the virus to isolate and bond different animal traits in a single host, B.O.W.s which inherit only the best traits can be created. For example, insect growth and vitality can be combined with mammalian intelligence. This concept was continued with Las Plagas and the C-Virus, with many of the most effective B.O.W.s created this way.


Hunters are a flagship B.O.W. line of products. Both Hunters and Tyrants achieved the most successful results as weapons in Umbrella experiments, and many subspecies were created due to their high demand on the black market.

MA-120 - The bII strain of the t-virus was capable of complex genetic manipulation in advanced species of hosts. While progress towards the creation of the Tyrant reached a standstill prior to the arrival of Sergei, successful hybrids with desirable traits became a possibility. Humans were chosen as the base for experiments due to their intelligence, and various animal genes were considered to give the host augmented abilities. In particular, the ferocity and natural effectiveness of reptiles made them an attractive candidate.
Homeless people were used as test subjects, and were injected with the virus in conjunction with reptile genes. These prototypes were referred to as MA-120.

Hunter Alpha (MA-121) - Further experiments with reptile/human hybrids produced the MA-121. Unlike the MA-120, the 121 was created using three-month-old human embryos to maximize the control over how they developed. After injecting the embryos with reptile genes using the t-Virus as a bonding agent, they were given growth promoters and successfully developed into stable organisms in just under a year. These prototypes showed excellent promise, and were named Hunter Alpha ("Hunter" for their tracking and fighting skills, "Alpha" for their prototype status).
Hunters were humanoid in size and shape. They had the hunting skills of reptiles and considerable intelligence to follow simple orders. According to the Biohazard 0 Kaitai Shinsho guidebook:
Intelligence decline, the bottleneck of human hosts, is caused by the t-Virus thoroughly eroding the dominant cerebral neocortex. Therefore the Hunter uses the genes of lower class organisms with only instinctive old brains such as the brain stem and cerebellum which have been discovered to compensate for cerebral functions and improve controllability.
Their intellect was on par with an ape, and trainers could teach them to follow around 10 spoken orders. They were social creatures able to cooperate with one another to distract and ambush prey. Their excellent senses allowed them to track down prey in a large outbreak zone.
Hunters were covered in green scales (some specimens were red in color, likely a purposeful modification to differentiate between certain individuals). All specimens were cloned from females and had visible vaginas, so whether or not Hunters could reproduce is completely unknown. Specific genetic modifications caused them to develop very resilient skin, which was amazingly on par with a Kevlar bullet proof vest, giving them extreme resilience in combat against armed targets. They had large claws
able to easily decapitate large prey, which was their primary means of attack. They also developed small sharp teeth, and they were almost certainly carnivores. They had extremely well-developed muscles which gave the incredible strength, and their speed and jumping abilities were especially impressive. They also displayed considerable climbing abilities, and could climb the side of large buildings. Their aggression and intelligence often resulted in sadistic behavior, and they enjoyed torturing prey to death and prolonging their suffering. A Hunter without a particular target will make no discrimination in it's attacks, and will kill Zombies as well as humans. Hunters are capable of spreading the virus, but the vast majority of those unlucky enough to be attacked will not have enough of themselves left to be infected.
The Hunter Alphas were a resounding success, and further experiments were performed with them in Umbrella facilities around the world. The Alpha was only a prototype, however, and before the Hunter could be mass produced combat data was required. Many cloned specimens were encountered by S.T.A.R.S. during the Mansion Incident, and others were encountered at Sheena Island and possibly Raccoon City.

Hunter Beta (MA-121) - Combat data recovered on the Hunter Alpha during the Mansion Incident was used by Umbrella to create a second MA-121 prototype: the Hunter Beta. During gene culture of a Alpha clone, modifications were made to the Hunter to fine tune it's speed and reaction time. Around 20 clones were created, and a truck of them carried the Betas into Raccoon City during the outbreak to test their combat abilities against survivors.
Being based on an Alpha, the Hunter Betas have similar combat abilities. However, several faults developed in addition to it's enhancements. It developed many growths on it's body, giving it less cosmetic charm. More importantly, one arm failed to develop fully, forcing the Beta to rely on a single arm. This is a considerable fault, as Hunters primarily use their claws in combat.
It's reaction time allowed it to detect and evade bullets at almost supernatural speeds.

Hunter MA-121 Mass Production Type - After the combat data on the Hunter Beta was recovered, the finished MA-121 was created using both of it's prototype models. This B.O.W., which is now the official Hunter B.O.W., was mass produced and sold as a flagship product. The finished Hunter model possessed the appearance of the Hunter Alpha, and the heightened abilities of the Hunter Beta.
The primary purpose of the Hunter is to locate and eliminate Zombie outbreak survivors who resist infection. They also are used as body guards and security, although their appearance limits their applications here. Mass Production Hunters have been in constant use throughout the years, and are still popular now. In particular, an army of Hunters were supplied to the terrorist group Il Veltro. After dispersing the t-Abyss Virus over the city of Terrigrigia using UAVs, countless Hunters were released on land to kill survivors and frustrate evacuation efforts.

Hunter R - After the success of the Hunter Alpha and recovery of it's combat data, many alternate models were produced by different facilities. Successful B.O.W.s were always difficult to create, and so now that creatures like Tyrants and Hunters were made, it became a mad dash within Umbrella to create products.
William Birkin's team, in addition to it's work on the G-Virus, t-Birkin, and the mass production type Tyrant, also created a new breed of Hunter. This Hunter was modified during development to focus on pure practicality, and it's reptilian attributes were magnified. It was called Hunter R (Reborn), and many
specimens were cloned and transported from NEST to Umbrella's above-ground Raccoon City facility, where they were to fight the Tyrant R in an experiment. During the outbreak, many specimens escaped and roamed both labs. They were strong enough to survive being completely frozen. All known Hunter Rs were eventually destroyed during the outbreak.

Hunter Mu - Hunter Mu was a miniaturized version of the Hunter R. Around half their regular size, these were designed to be easier to transport and conceal. Like the Hunter R, all specimens were destroyed.

Hunter Gamma (MA-124) - Developed in Europe, the Hunter Gamma (MA-124) was an alternate model not based on the Hunter Alpha. They were created using an amphibian base (a frog) and injecting it with the t-Virus and human genes. This Hunter was nicknamed "Frogger" by the development team. Froggers were sent to Raccoon City during the outbreak along with the American Hunter Beta to gather combat data.
This model of Hunter did not develop pronounced eyes, like other amphibian hosts, but it could detect prey using its non-visual senses (hearing, in addition to it's awareness of air and water flow). It's size was that of a human, like other Hunter models, and it developed much smaller claws than the MA-121. It's primary means of attack was the same as the frog B.O.W. Lurker: it used it's enlarged mouth and powerful digestive system to devour prey whole. It lacked the tongue of Lurkers, but it's arms made up for this. It had the same jumping abilities as the Lurker and MA-121. The Frogger could fight on land and in water, which was it's biggest advantage over the MA-121, but it was otherwise inferior due to it's lack of intelligence, blindness, and dependence on moist environments. Despite it's shortcomings, it was the best B.O.W. Umbrella could create for marine combat. After the trial in Raccoon, it was miniaturized like the Hunter Mu for ease in transportation and mass produced at the Caucasus Facility. Some models were purchased by Javier Hidalgo.

Glimmer - When B.O.W.s sent to be disposed of at the island Morpheus was charged with overseeing escaped, the Glimmer was among them. Based on their appearance, they seem to have been a prototype for the Hunter Gamma, or for a new breed based on it. They were slightly smaller than Froggers, and instead of devouring prey whole they vomited enormous amounts of their highly potent stomach acid directly over prey. They developed many eyes which glowed red, and preferred pitch-black environments. They darted around in the dark, with only the blur of their glowing eyes visible, to confuse prey as they approached. This is what earned them their name "Glimmer". Their unique attributes may have been wild mutations that occurred after they escaped confinement, and based on their numbers they seem to be capable of reproduction.

Hunter II - Albert Wesker stole the Hunter master data and a cloned embryo of the Hunter Alpha during the Mansion Incident and gave them to Umbrella's rival corporation. The corporation used their advanced technology to create the Hunter II, which was directly based on the Hunter Alpha. These B.O.W.s were sold as a superior Hunter alternative on the black market before Umbrella even finished it's mass production model. Since Umbrella previously had a monopoly on the virus and B.O.W.s, this was a critical blow.
The Hunter II was biologically identical to the Hunter Alpha for the most part. The key difference was the Hunter II was equipped with a device on the side of it's head. This device picked up special frequencies from surveillance drones and directed the Hunter II accordingly. The automated drones acted as scouts in an area, and when specific targets were detected, the drone would signal the Hunter II to come to it's
location. This allowed the user to accurately pick out targets in an area, rather than sending in the Hunter to kill blindly (while other Hunters can be trained when and where to hunt, they cannot differentiate between targets). It also eliminates the need for trainers, and makes them capable of performing assassination missions (something only Tyrants could originally do). Without the drones or headset, they were essentially just Hunter Alphas.
Many specimens were used by Wesker at Rockfort Island during the raid by H.C.F..

Sweeper - Sweepers were a modified subspecies and companion model of the Hunter II. They were created by the rival corporation to kill targets that the Hunter II missed. If the Hunter II is a scalpel with surgical precision, the Sweeper is a bomb which clears out an area. They were modified to secrete poison from their claws, perhaps by introducing new genes, which would ensure even those who escaped wouldn't survive. It's running and leaping abilities were also enhanced. To differentiate it from the Hunter II, it was modified to have red and purple skin.

Hunter Delta - Umbrella began work on another MA-121 prototype called Hunter Delta, to further refine and enhance the abilities of the mass production Hunter. However, the rise of superior Hunter models created by the rival corporation on the black market, combined with the business suspension decree in the US, forced Umbrella to shelve further MA-121 experiments in favor of mass production of different, cheaper B.O.W.s and new alternatives. The Delta prototypes and their development data were sent to be stored away in Russia, and were destroyed during an attempt by Wesker to steal them.
Exactly how the Hunter Delta was enhanced is unknown. It's appearance was identical to the Alpha and mass production types.

Hunter Elite - The last known Hunter type created by Umbrella was the Hunter Elite. It was created using reptile and amphibian genes with a human embryo, in an attempt to create a model with the abilities of both the mass production type and the Hunter Gamma. It was also modified to have even tougher skin, making them harder to kill. It's claws were smaller than Alpha-based Hunters, and were curved like hooks.
Around a dozen presentation models were kept onboard the Spencer Rain, and were all destroyed when the ship crashed.

Tick - An apparent Hunter breed created using insect genes at the Arklay Mansion. Little to no background information exists on these creatures.

Other Hybrids

Besides Hunters, the Umbrella Corporation produced other B.O.W.s which utilized genes from multiple species of creatures:

Plague Crawler - During very early experiments with the first strain of the t-Virus, Marcus created the Plague Crawler by incorporating the genes of various insects into a single host. Insect biology is very simple and easier to manipulate when compared to more complex organisms such as humans. The Plague Crawler was nicknamed DALI, which stands for "DNA Arranged, Lack of Intelligence". DALI was very large, like most infected arthropods. It had two sickle-like arms for slicing and stabbing prey, and a strong exoskeleton capable of deflecting small caliber firearms. Based on it's appearance, it appears to have been originally based on a dragonfly. It could climb surfaces and hang from the ceiling to drop down and ambush prey. It appears to have been capable of reproduction, and could create a large hive from a sticky red material. Due to it's limited intelligence and combat mediocrity, it was considered a failure and dropped. However, the Queen Leech recreated the Plague Crawler as a part of it's B.O.W. army, and several specimens meant to be disposed of were instead sold to Javier Hidalgo as a cheap B.O.W..

Chimera - A creature created alongside the Hunter Alpha at the Arklay Mansion, the Chimera was a moderate success. It was named after a mythological beast comprised of three different animals. The term chimera is also a term used to describe organisms created with the genetic material of multiple animals.
Chimeras were created using fly genes and the t-Virus on a fertilized human ovum, then letting a surrogate human mother give birth to it. That's a nightmare. The goal was to incorporate the rapid maturation of a fly into a humanoid B.O.W., and as such Chimeras developed just as rapidly as flies.
Chimeras are no more intelligence than a fly, making their attack patterns monotonous and predictable. They can walk upright on two legs, and quickly run by crawling on the ground.
They developed small wings, but these were not large enough to make them capable of flight. Instead, they could expertly climb on walls and ceilings. They would nest in narrow spaces such as ventilation shafts. Chimeras had limbs tipped with sharp claws that they used very stealthily. Their warped, complex skeleton gave them agility and destructive power exceeding the Hunter. They also had noticeable reproductive capabilities: inside crevices in the Chimera's body were countless maggots, which could develop into more Chimeras.
Chimeras overran the underground lab at the Arklay Mansion during the Mansion Incident. When the mansion was destroyed, the Chimera master data was lost, but Birkin recovered a cloned Chimera embryo beforehand. While Chimeras were previously considered failures due to their low intelligence, Umbrella, in it's desperate state following the Raccoon City Destruction Incident, approved them for mass production at the Caucasus Facility anyway. The psychological impact the Chimera left on foes due to it's appearance made them popular B.O.W.s, and they are still in use by bioterrorists.

Anubis - After the Rival Corporation began manufacturing superior Hunter models, Umbrella desperately attempted to retaliate by creating alternatives to the Hunter. The Anubis B.O.W. was created using insect genes with a bat embryo. It's main purpose was to have unmatched speed and maneuverability on the battlefield. After development, all of it's digestive organs were removed to make it lighter. After being released from cryogenic storage, it could only remain alive for a limited amount of time before it starved to death. It was largely skeletal, with the frame of a bat. It's limbs were extremely thin, but were strong enough to resist gunfire due to insect genes strengthening it's bones. It was also modified to develop claws, which were it's primary means of attack. It's jumping and climbing abilities were outstanding, and it could quickly transverse an environment and outpace prey. It was named after the Egyptian god of the dead, and it's skull vaguely resembled Anubis' most popular depiction. This B.O.W. was mass produced and sold to Javier Hidalgo.
While no B.O.W. could match it's movements, it failed to replace the Hunter, as Hunters are in continued and common use today.

Brain Sucker - During the Raccoon City Destruction Incident, an insect fed on the corpse of a reptile infected with the t-Virus. Genes from this reptile were piggy backed into the insect via the virus, creating the only confirmed natural genetic hybrid. This insect, called the Brain Sucker, reproduced and feasted on survivors of the outbreak. It grew to the size of a human, and resembled two creatures entangled with one another. It shared similarities with the Drain Deimos, and both seemed to originally be blood-sucking, flea-like creatures. The Brain Sucker was named for it's primary diet: it would use it's two sharp tongues to crack open human skulls, then suck out their brains.
The Brain Sucker had five legs instead of six, and was capable spewing toxic venom from a distance.

Super Humans

Human hosts who slowly adapt to the Progenitor Virus gain incredible new and enhanced abilities without losing their human form. These "Progenitor Humans" gain enhanced strength, speed, agility, and intellect. The RE developers have also toyed with the idea of adapters gaining psychic abilities. They also cease ageing and gain outstanding regenerative abilities. This, along with strengthened body tissue and overall endurance, makes them essentially become immortal. The only visible mutation that sets Progenitor Humans apart is the development of glowing red reptilian eyes.
Progenitor adaption requires special genes that can produce antibodies capable of weakening the virus in order for the host to survive and retain their form. However, these exceedingly rare individuals have only become rarer throughout history. Even if someone with such genes became infected with modern Progenitor, they would still suffer horrible mutations (like Lisa Trevor) or die due to it's lethality increasing over the years.
While the official goal of the t-Virus was to create B.O.W.s, it's actual purpose was to create a strain of Progenitor weak enough for the Umbrella founders to adapt to it and gain immortality. Every main virus from t-Marcus to t-Birkin either failed to recapture the capacity to create Super Humans, or was still too lethal for human hosts to become anything more than Tyrants. However, several variant strains of T recaptured this ability, and the 2003 Perfected t-Virus may have as well. Even then, the t-Virus was specialized to create monsters, not enhanced humans, so "t-Humans" always lack the same biological perfection as Progenitor Humans. The same goes for other super human Viruses like G and t-Veronica. The only known virus to perfectly replicate this mutation is Uroboros (and maybe t-Phobos).
The several known t-Humans in existence who have perfectly bonded with the t-Virus and gained powers are covered below:

The Wesker Children

Oswell E. Spencer secretly planned to create a new world utopia made up of Super Humans. These adapters needed to be elites who shared in Spencer's ideologies. Hundreds of children who were born
to parents of significant accomplishments (they would be most likely to carry advanced genes) were gathered and indoctrinated. This was the Wesker Project, named after the project's head researcher at the time. Thirteen children eventually made it to the latter stages of the Project, and they were all given the surname Wesker. They were monitored by Umbrella as they grew up, and were given employment at the company. Subject number 13, Albert Wesker, became an Umbrella executive while still in his teens, was the co-creator of the t-Virus, and went from head researcher at the Arklay Mansion to secret agent in the Intelligence Division. Subject number 12, Alex Wesker, was the only subject who became aware early on of the Wesker Project, and Spencer was pleased enough with her to make her it's new head researcher.
During the creation of t-Birkin using the V-ACT strain of Epsilon recovered during the Mansion Incident, William Birkin discovered another mutant strain (which I will refer to as "t-Wesker"). t-Wesker was experimented on rats, and it was discovered to be capable of reviving the dead (without them becoming Zombies or monsters). Birkin could not devote more time to this virus due to his ongoing research with T and G, but he gave a sample to his friend Albert Wesker. Wesker planned on faking his death and leaving Umbrella, and this Virus was his chance to do so. What Birkin didn't know was that t-Wesker was highly lethal in humans. Luckily, Wesker had excellent genes compatible with Progenitor-based Viruses, allowing him to produce antibodies to weaken t-Wesker. During the Mansion Incident, he injected himself with t-Wesker then allowed the T-002 Tyrant to kill him. Minutes later, he came back to life as a t-Human.
When Spencer learned of this, he acquired t-Wesker and had the twelve other Wesker Children injected with it, to see who was as worthy as Albert and who was not. Eleven could not survive infection, and only Alex survived. She gained some minor mutations, but did not develop true powers and acquired a deadly sickness.
t-Wesker was most likely based on the Crimson Head or Licker strain of the t-Virus, so it is more dependent on V-ACT. It is more like Progenitor than other strains of T, as it will kill those who do not adapt (although the Wesker Children killed by this strain could have become Zombies or Monsters). When t-Wesker is first injected, it causes intense pain as it alters the host's biology. The pain alone could kill those of a weaker constitution. Rats are much more tolerant of this initial mutation, but in humans it is fatal. Only natural virus adapters like Albert and Alex can hope to survive this stage. After the virus has bonded with the host, they will experience no further symptoms until V-ACT occurs and reactivates the virus. Then, hosts who have perfectly bonded will gain enhanced abilities and eye mutations. Since t-Phobos adapters must also experience V-ACT before becoming Super Humans, it is likely that t-Phobos is based on t-Wesker.
The full nature of t-Wesker's abilities is only seen in Albert:

Albert Wesker - Albert fully adapted to the t-Virus, and gained powers very similar to Progenitor Humans, including red reptile eyes. These eyes glowed whenever he experienced intense emotion.
It is not known whether or not Albert developed enhanced intelligence, but he continued to age, as seen by wrinkles on his face. While he suffered the effects of time, his regenerative capacity was greater than any other mutant in the entire series. He was as close as one could get to unkillable, and when he literally died on two separate occasions (the Mansion Incident, when his organs were ruptured and his head split open; and at the Caucasus Facility, when he was torn apart and suffered total brain death), he
was recovered by the virus and completely restored. According to Birkin, as long as a tissue fragment remains, he will always fully regenerate. This is one of the greatest examples of the power of the virus, and even then, t-Wesker is thousands of times weaker than Progenitor itself!
Besides enhanced healing, Wesker's tissue was strengthened. Hunters have skin that can withstand bullets, and Tyrants explosions, but the strengthened tissue of Wesker could withstand direct hits from rockets. When Chris Redfield punched him in the face, his body was so hardened that it caused Chris to shake his hand in pain (the same Chris who regularly punches B.O.W.s and boulders).
Wesker's strength was greatly enhanced, allowing him to rip regular humans apart, bend steel, and throw giant missiles like darts.
Wesker's speed and reaction time was greater than the Hunter Beta. When he moved, he appeared to teleport due to his speed being greater than the processing speed of the human eye. This was at least true for short bursts, but he could still run long distances faster than any animal. His jumping skills were comparable to a Tyrant, and he could pursue Chris up a long ladder with a single leap. Albert Wesker was essentially a human Water Bear - almost the perfect organism. However, due to his infection with an unstable mutant strain of the imperfect t-Virus, he did not reach the level of an Uroboros or Progenitor Human. Not only did he continue to age, but the virus activity in his body was unstable. If he continued the way he was, he would eventually lose some of his abilities (like Mary Gray; see below), die, or randomly mutate. In order to remain stable, he needed regular injections of a special serum called PG67A/W. The "PG" likely stands for Progenitor (supported by the fact it seems to have been produced by the TRICELL corporation), while the "A/W" probably stands for Albert Wesker. If he took too much of the serum, it acted as a poison and weakened his abilities. If Wesker finished his plans, it is likely his Uroboros Virus would eliminate this weakness.
Chris and Sheva Alomar used this serum to overdose Wesker, then, in his weakened state, killed him by plunging him into a volcano and decapitating him with two RPGs.

Alex Wesker - Alex had greater genes than most people, but not great enough to fully adapt like Albert. Her eyes developed slits like Albert and turned purple. Purple and red eyes are both caused by bursting blood vessels in the eyes, and so the difference in color is not indicative of a different mutation. She failed to gain powers, however, and developed a sickness that slowly destroyed her body over the course of the next decade. The Virus was essentially killing her slowly, instead of instantly.
Despite this, Alex was also strengthened in other ways, like how Zombies are simultaneously weakened and strengthened by the virus. When t-Phobos was triggered inside her body before shooting herself in the brain, her previous infection with t-Wesker not only allowed her to survive t-Phobos (which is fatal in women), but both viruses together allowed her to survive shooting herself and transformed her into a monster.
Since Albert did not develop eye mutations until after V-ACT, it can be assumed Alex died once before her suicide attempt.

Al Lester

As explained in the "Plantae" section, the wife of hospital administrator Albert Lester was treated with a strain of the t-Virus called T-JCCC203. She became a Zombie which led to an outbreak that destroyed the hospital and left it abandoned. Her corpse infected a plant and turned it into a monster. This plant was discovered by Lester, who now lived in the woods and regularly visited the derelict building. He mistook it for his wife and called it "Dorothy". He fed the plant humans and animals throughout the same year, until a group of survivors from the Raccoon City Incident destroyed it. All of this I already covered. But Al Lester himself became infected by the plant by accident. Instead of becoming a Zombie or monster, he retained his human form and gained incredible vitality exceeding a normal human. This makes him a t-Human of a sort.
Lester lacked eye mutations, and the only visible mutation was a patch of green skin on his belly. He no longer felt pain or temperature, and descended into madness. These symptoms suggest his brain and nervous system may have been damaged, as Zombies experience the same symptoms due to necrosis. Lester's tissue was very strong, allowing him to survive multiple gunshot wounds, although his vitality was not as great as Albert Wesker or even Tyrants, and he was killed when the hospital collapsed.
Despite his insanity, Lester retained his intelligence and memories. He lured campers and hikers to the hospital, then donned a black hood (like an executioner) and chopped them up with an axe to feed "Dorothy". This behavior is the reason for his nickname: Axe Man.
The reason Lester experienced such unique mutations was due to his Virus being especially weak, preventing drastic mutations and extreme necrosis. His virus was weakened due to both the following reasons:
1. He was infected with T-JCCC203, which was a strain designed to eliminate disease without killing the host. His increased vitality is simply due to the natural strengthening of the virus which allows hosts to overcome disease. When Dorothy Lester was first injected, she recovered at first, then later degenerated into a Zombie. Al was only infected for less than a year, and so he too could have eventually degenerated into a Zombie. His insanity could be his "itchy, tasty" stage.
2. The virus he was infected with passed from Dorothy to a plant to Lester. The Virus was weakened due to recombination (see the first post of this Analysis). The fact Lester developed a green rash shows the virus developed new mutations from it's previous plant host. The virus was also active for five years in the wild before Lester was infected, so the possibility of random mutations is very high. These factors caused his state as a human to be prolonged farther than with Dorothy, who turned in days.

Mary Gray

Philosophy University student Mary Gray in Australia was also a t-Human. When she was younger, Mary was diagnosed with a deadly blood disease. As a treatment, she was administered the t-Virus by Ryan Howard, who discovered she had compatible genes. Mary adapted, gaining powers. Exactly what strain of T she was injected with is unknown, but it seems she was infected with Perfected T, giving us an example of a t-Human created with a "mainstream" t-Virus.
Mary exhibited enhanced speed and strength comparable to Albert Wesker, although she lacked his eye mutations and near immortality. This is evident as she was capable of taking on Chris Redfield, Tyler Howard and others in close combat, but was much more easily killed. It is unknown if she aged. Mary's
most noticeable mutation was an increase in brain power: her IQ sky rocketed to 230. The official description for BIOHAZARD: The Stage also claims she was capable of clairvoyance.
Like Albert, her relationship with her virus was not stable. The virus was regularly metabolized from her body, and so she needed to be regularly reinjected in order to retain her strengthened biology and resist her disease. She therefore wore a bracelet which regularly provided her with small doses of the virus.
Mary's artificially heightened intellect made it difficult for her to relate to others, and made her prone to insane outbursts. She plotted to use the t-Howard virus to reset humanity. When her plans were discovered and after a short skirmish, she became upset and used her bracelet to take a massive overdose of the Virus. This dose was too much for her body to adapt to, and the rapid mutations caused her cellular integrity to break down. The result was random and dramatic changes that turned her into a giant monster. This monster was destroyed with a rocket launcher blast.

Miscellaneous T Mutants

The last five known creatures to cover do not fit into any of the above categories, and so I have lumped them here together at the end. All of them were created under extenuating circumstances which led to their entirely unique nature.


Umbrella used special paramilitary units such as the U.B.C.S. (Umbrella Biohazard Containment Service) and U.S.S. (Umbrella Secret Service) to deal with uncontrollable outbreaks. These soldiers suffered heavy losses, and betrayal of company secrets was a very real threat. In late 1998, following the destruction of the U.B.C.S. during the Raccoon City Destruction Incident, Umbrella developed a new B.O.W. specifically designed to clean up outbreak zones without leaving evidence of Umbrella's involvement. These were called "Undertakers" or "Trashsweepers". A unit of these creatures were sent to clean up the outbreak at Sheena Island, and it is unknown if they were used again.
Undertakers were human clones modified during gene culture, presumably with help from the t-Virus. Unlike other humanoid B.O.W.s like Zombies and Tyrants, Undertakers were fragile, and their vitality was equal to a normal human being. The most prominent modification was the development of extremely corrosive chemicals that made them appear to have green blood. When Undertakers died, these chemicals increased in potency and caused the entire body to dissolve, leaving no evidence the Undertaker was ever there. Undertaker intelligence is purposefully lowered to render them compliant, and to lessen their instincts of self-preservation. They are left with just enough intelligence to interpret hand signals and to operate firearms. As a side effect of their modifications, Undertakers have a distorted appearance. They are smaller than typical humans, and display ape-like mannerisms and posture. Their voices are distorted, and they make screeches and growls similar to large felines. Any other physical features are impossible to observe due to them wearing black uniforms similar to those seen on the U.S.S., including the gas mask. Undertakers are all given night vision goggles and submachine guns.
Each Undertaker unit has a single human handler, who they are trained to obey. After completely clearing out an area, Undertakers will kill themselves, leaving only the handler to be evacuated. Despite their simple intelligence and frail bodies, Undertakers are cheap to produce and completely expendable. Their numbers and ability to use guns makes them capable enough, and the fact they are completely destroyed upon death makes them great for eliminating evidence and witnesses.
Besides being tools for Umbrella itself, Undertakers could also potentially be used as a companion product with the Hunter and the t-Virus itself: the virus could be used to plunge enemy territory into chaos, the Hunter would track down survivors, then Undertakers could clean up the mess, leaving the infrastructure intact but wiping out all life.


It was well known by Umbrella that the t-Virus caused hosts to develop enhanced hearing, especially when they also suffered ocular damage (best seen in the Zombie, Licker, and Lurker). But the exact nature and extent of these enhancements were poorly understood. In 1996, Umbrella began experiments to test this phenomenon. A death row inmate who was supp
osed to be used for pharmaceutical testing was chosen as a test subject, and was nicknamed "Alpha". This prisoner was subjected to extensive and cruel experiments, beginning with a lobotomy using a metal rod. It was stated by a researcher that this operation was to remove discomfort, although it was more likely done to make him more compliant. Afterwards his eyeballs were removed, and he was injected with several strains of the t-Virus along with anabolic steroids. The purpose of the steroids was likely to strengthen his body to survive infection with the virus, just like how Tyrant hosts undergo body strengthening surgeries to survive mutation. This raises the question of whether or not the mutations seen in this subject were related to the Tyrant mutation, although the fact multiple variant strains were used, and that the first Tyrant had not yet been created makes it impossible to say for sure.
The test subject's skull had the top removed so the researchers could examine or even manipulate the brain in how it adapted to the changes in hearing. As expected, the subject's hearing was greatly enhanced. While normal blind humans learn to compensate for the loss of sight with their other senses, the virus causes compensating mutations that result in literal enhancements to how the host perceives sound.
As a side effect of the viruses and steroids, the subject's muscle mass, size, and weight all increased, as well as his aggression. To combat this, the researchers removed his genitals to limit testosterone output. His left arm mutated into a stiff claw resembling a tree trunk. Eventually, his strength reached a higher level than was anticipated, and he broke free from his restraints, killed five researchers, and escaped. This monster, named Pluto at some point by Umbrella (after the ruler of the underworld in Greek mythology), used it's advanced hearing to navigate and hunt in pitch darkness. In 2002, it was evaded by Fong Ling then killed by Bruce Mcgivern. While it's fatty tissue absorbed most damage from firearms, it's exposed brain served as a weak point. When Bruce damaged the brain, it hung loose from the skull, shortly before Pluto died.
According to a developer, Pluto's attacks towards Bruce were not violent, but playful. Pluto wanted to "hug" him like a kitten. I honestly can't tell if the dev was joking or not, but he probably was.


South American crime syndicate leader Javier Hidalgo had a wife named Hilda and a daughter named Manuela, whom he loved fiercely. Hilda was diagnosed with a fatal disease native to the region, and an Umbrella researcher sold him a sample of the t-Virus designed to cure her. This was before the similar incidents with Dorothy Lester and Mary Gray, and it is unknown if this strain was related to T-JCC203. Hilda's condition improved after injection with the virus, and her body strengthened. But soon after she entered a coma. This probably means Hilda, like Dorothy, was doomed to become a Zombie. Javier, desperate, repeatedly injected her with more of the virus. This caused drastic mutations due to excessive virus activity, similar to when Mary Gray overdosed on T and turned into a giant monster. Hilda's original form was lost as her body was overwhelmed by random mutations, and she turned into an unrecognizable monster. Javier was unwilling to dispose of her, so he locked her away and told Manuela he had taken her to paradise. Years later, Manuela ran away after discovering she was treated with the t-Veronica Virus. Javier, enraged, unleashed many of his B.O.W.s purchased from Umbrella and the rival corporation into the surrounding region, including Hilda. Hilda devoured many people from beneath the water of the flooded Mixcôatl village, and confronted US operatives Leon Kennedy and Jack Krauser twice. She was killed during her second encounter with the duo.
Hilda appeared to be an amphibious creature with traits reminiscent of various Amazonian creatures. This could be a coincidence, or an adaptive mutation in response to her environment. Remember, the Progenitor Virus created all life on Earth, so a virus derived from it being capable of turning a mammal into an amphibian is entirely possible.
Hilda's head and body fused into a long, sleek body that made it an excellent swimmer. The remains of her skull developed mandibles and glowing eyes. On the top of her head/body, her brain was exposed, and both it and her face were covered by translucent domes. During her first fight with Leon and Krauser, they caused a church bell to fall on top of Hilda, destroying the domes, which left her brain exposed as a weak point during their second fight. Hilda's arms were replaced with tentacles capable of rapid movement. She developed a tail capable of shooting giant barbs. These barbs are coated in poison, and were used to cripple Krauser's arm. Hilda's tough skin was highly resistant to gunfire.
Despite her heavily altered appearance, Hilda retained some of her memories and personality. While she was highly aggressive and driven by intense hunger, Hilda could be calmed by the sound of her daughter's voice, particularly when Manuela sung a lullaby Hilda would sing to her in the past. Hilda also would not attack her husband, Javier. Hilda's skin and eyes changed color depending on her mood: when angered, she became orange and red. When calmed, she turned blue. She was also blue while swimming, to act as camouflage. Before dying, her eyes reverted to their original brown form, and she shed a tear, causing Manuela to recognize her.


Nyx was a fleshy blob with no discernable shape or form, besides being covered in many tentacles and have a vital organ at it's core. Nyx was named after the Greek goddess of night, who is incidentally also the mother of Nemesis, Hypnos and Thanatos. This creature was stored in Raccoon City in a cargo container. A rogue U.S.S. member attempted to steal it during the outbreak, but it escaped and devoured a group of U.B.C.S. along with the Tyrant R. It was destroyed by a group of survivors who damaged it's vital organ. Nyx consumed organic matter by absorbing it into it's skin, and partly digested remains could be seen extending from it's body. It developed a humanoid shape after consuming humans, suggesting it was able to incorporate the biology of it's food into it's own body.
Fitting it's name, Nyx was the most mysterious creature in the entire series. All we know for certain is that Umbrella was responsible for it, and that it was valuable to them. The base organism used and it's purpose are completely unknown. Despite being in this analysis, we don't even know if it was created by the t-Virus. Over the years, many fans have made theories regarding Nyx, and these explanations make the most sense to me:
1. It is a variant form of the Nemesis parasite. This is supported by it's tentacles, growth, and tendency to devour Tyrants.
2. It is a creature created from the G-Virus. This is supported by it's similarities to the fifth form of G-Birkin, including the partially devoured body parts sticking out of it.
3. It is some kind of fungus infected with the t-Virus.


D.I.J. was a rat experimented on using the t-Virus at Rockfort Island. Like some other hosts, it displayed a dramatic increase in intelligence. It witnessed the events that occurred during the outbreak at Rockfort and the Antarctic base, and recorded them in a diary. D.I.J. managed to escape, and it's whereabouts are currently unknown.
D.I.J. is the most well-developed character in the series, and the most powerful B.O.W. ever created with the t-Virus. It is not a joke character any more than Tofu or Albert Wesker, despite claims to the contrary by some so-called "fans". Being a full adapter to the virus, D.I.J. is the key to creating a cure to all viruses derived from Progenitor, likely making it a target by various groups. This explains it's disappearance following CV, and it's motives are unclear at this point.
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Added some more Nemesis info from here:

Also apparently the Grave Digger is actually an arthropod, like a millipede. Guess I'll have to fix that at some point *groan*
Thanks @News Bot
According to the designer, that device in the Tyrant's head in RE2make is it's power limiter now. The coat is just for protection.

Dr. Wunderbar of Project Umbrella speculates it might send inhibiting electrical signals to the hypothalamus and pituitary gland.
So question, if the T-virus makes mammals, which all signs undoubtedly point towards, sterile, how did wesker have a son? Is there a virus he could've acquired to reverse the effect or is it more likely he was in a grey area due to requiring medication to keep his powers?
So question, if the T-virus makes mammals, which all signs undoubtedly point towards, sterile, how did wesker have a son? Is there a virus he could've acquired to reverse the effect or is it more likely he was in a grey area due to requiring medication to keep his powers?
Wesker's quick business with jake's mom happened before 1998 when he wasnt a superhuman.
Has anyone ever figured out the main stages in which T-Virus progresses before Zombification occures? Or are the symptoms always different within hosts?
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Has anyone ever figured out the main stages in which T-Virus progresses before Zombification occures? Or are the symptoms always different within hosts?
I think the best description from a first person view was the itchy tasty diary in RE1. Although it’s anecdotal, it gives descriptive detail on how the host changes and their mental degradation. You also have to take into account that the T-virus has the most developed strains out of any other, so the rate of zombification can vary significantly from each individual.

There is also secondary infection where they change into Crimson Heads or Lickers, which is also left ambiguous how fast they mutate.
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