Carlos Oliviera (カルロス・オリヴェイラ, Karurosu Orivera) is originally from a South American anti-government guerrilla group, his nationality is unknown (possibly Portuguese or Brazilian, due the Portuguese family name). After government forces wiped out his former organization, Carlos was scouted out by the Umbrella Corporation to join the Umbrella's UBCS. He joined the force and was assigned to Delta Platoon, Company A, along with Nicholai Ginovaef and Mikhail Victor. Despite his violent background, he is warm-hearted and known for joking around. In Resident Evil 3, Carlos assists Jill Valentine throughout the game as the two of them attempt to escape Raccoon City. At one point Jill becomes infected by the T-virus after a battle with the Nemesis. At this point Carlos becomes playable so that the player can prepare a vaccine for Jill. Ultimately he is successful in escaping the city along with Jill. He reprises his role in The Umbrella Chronicles. The events of Resident Evil 3 are revisited in The Umbrella Chronicles scenario "Raccoon's Destruction", in which Carlos is a playable character alongside Jill Valentine. Carlos is voiced by Vincent Corazza in Resident Evil 3 and by Kim Strauss in The Umbrella Chronicles and personified by Oded Fehr in the films Resident Evil: Apocalypse and Resident Evil: Extinction. In the live action films, his name is spelled Olivera.
Source: Wikipedia, "Carlos Oliveira (Resident Evil)", available under the CC-BY-SA License.