Resident Evil 4
Leon first encounters Luis in a dilapidated house while searching for Ashley.
Luis is a former Los Illuminados researcher, and as an expert on parasites he is able to remove their eggs.
Although he is usually aloof and tends not to openly display his feelings, when he learns that Leon and Ashley have been implanted with Plagas he makes an extremely dangerous detour back to the Salazar castle, and retrieves a drug that will slow the growth and controlling power of the parasite.
He also has excellent combat abilities, which can be seen during the siege on the mountain hut where he assists Leon with his trusty Red 9 pistol.
Height: unknown. Weight: unknown. Blood type: unknown. Age: 28 (as of 2004 / Resident Evil 4).