Luis Sera was a womanizing scientist who worked for the Los Illuminados. At first, he believed he was just conducting research on the ancient parasites but soon discovered he was participating in a plot to take over the world. Luis tried to contact an old college friend, who he thought was still alive. Ada Wong intercepted the e-mail, instead, and responded to Luis, claiming she could help, but that she would need a sample of the virus in return.

Luis escaped from the Los Illuminados base and began his search for the parasite sample. He was caught and locked in a closet; Leon rescued him only for the both of them to be captured by Bitores Mendez, the village chief. When Leon and Luis managed to escape, Luis thanked Leon for his help and went off to find Ada and the sample. Luis ran into Leon again in a cabin that was under assault by Ganados. Luis, good with a pistol, helped Leon fight off the attack, and noticed Leon and Ashley were infected. He ran off to get medicine for the infection and bumped into Ada, who reminded him about his obligation to secure a sample of Las Plagas in exchange for her help.

In the Salazar Castle, Sera finally located the sample. However, as he was going to hand it to Leon, he was stabbed through the chest by Saddler, who took the sample with him. Before dying, Luis gave Leon medicine that would slow the growth of the parasite, buying him enough time to find a cure.