Luis Sera was a scientific researcher who hailed from a rural, isolated mountain village in Southern Europe. A shameless self-professed ladies man, Luis was particularly interested in the study of parasites. After supposedly spending some time in Madrid he returned to his native village in the rural wilderness to find everyone infected by a strange parasite and the region under the rule of an ancient cult known as the 'Los Illuminados'. Due to his background, the leader of the cult, Osmund Saddler, decided to recruit Luis to further the research rather than simply infect him.
History
Luis had been brought up in this region and his grandfather used to hunt in the area long ago, teaching all about many secret hiding places and hidden passageways buried in the mountains. He is also a self-confessed ladies man. Intrigued by the unique properties of the parasite, Luis readily accepted the offer without really thinking about the implications and dark intentions of this strange religious group. He began extensive studies of Las Plagas and determined that they were social organisms with properties similar to many other known parasites.
For the initial stages of the research, Luis began searching for a practical and safe way of removing the Plaga from the host subject. Although this task had been given to Luis with this guise, Saddler's real objective was to find a way to ensure that the Plaga could not be removed from the body easily. Eventually, Luis decided the only safe and viable way to remove the Plaga was through exposure to a special radiation. However, this needed to be done before the plaga reached maturity otherwise the host may be killed during the procedure.
Eventually countless number of Ganados were created and well as several all new Plaga-based B.O.W.s. Even with the knowledge that Saddler was going to abuse the results of these experiments, Luis could not pull himself away from his research and was ashamed to admit that his pure fascination with Las Plagas blinded him about the true intentions of the research by the Los Illuminados. As a result, he felt he was just as responsible for the current situation as Osmund Saddler himself was.
South Europe Incident
In desperation and not having any trust in the local police, he sent a confidential e-mail to a trusted colleague and college alumnus, detailing his plight. However this e-mail was intercepted by Ada Wong, an agent of the secretive corporation known only as 'The Organization.' Ada then made direct contact with Luis and offered to take him into protective custody in return for a control Plaga specimen, which was cultivated by Saddler. Albert Wesker also learned about the existence of the parasite, and wished to acquire the sample for his own group; The 3rd Organization.
However, shortly after this, Saddler became suspicious of Luis' true motives and had him apprehended and injected with Las Plagas. However, through unknown means, Luis managed to escape and successfully removed the Plaga from within his body before it hatched. He also stole the control Plaga specimen.
He made his way back to the Pueblo and hid the sample in the woods. He was eventually captured once more and locked up in an abandoned house until he could be transported back to Saddler's research outpost on a nearby island. He was later rescued by Leon S. Kennedy before they were both confined and scheduled for execution by the village chief, Bitores Mendez. After managing to escape once more, Luis evaded capture until nightfall. He came across Leon's comatose body near the lake and left him a note detailing the whereabouts of Ashley Graham and to warn him about the ferocious 'El Gigante' B.O.W.
He later took refuge in a barn house as the storm grew worse outside. Eventually Leon and Ashley caught up with him and he assisted them in holding off the Ganado horde when they laid siege to the house. Soon after this he met up with Ada Wong and went to recover the sample for her. He caught up with Leon once more in Ramon Salazar's castle but was killed by Osmund Saddler. With his dying breath he told Leon to recover the control Plaga sample at all costs. He also gave him some pills that would suppress the growth of the parasite within his body for a short time.