Carlos Oliveira was a Latin-American mercenary who at a young age joined South American guerrilla forces but was eventually captured by government military forces and sentenced to death for his crimes. He remained on death row for an uncertain amount of time.
However he was under surveillance by Umbrella who were impressed with his fighting and tactical abilities and therefore offered him a contract to work with them in exchange for his freedom. Umbrella then worked out a deal with his captors and eventually he was released into their care. Umbrella then brought him into the USA and offered him a role in their UBCS (Umbrella Biohazard Countermeasure Service) military force as the youngest member of the team.
He and the rest of his squad were dispatched to Raccoon City where a critical t-Virus
outbreak had occurred. His official mission was to rescue civilians and attempt to secure the city - although other members of his team were given additional duties which he was not aware of. When they reached the city they all realised that the situation was far worse than they had been briefed - most members of the UBCS were killed by Zombies and other B.O.W.s (Bio-Organic Weapons).
He and a few other members of UBCS managed to band together and form a makeshift base of operations in an underground train car. Their goal was to enable the power to the train line so that they could eventually use it to leave the city. The underground area was well secured against the outdoors which meant it was perfect for hiding from all of the monsters that awaited them - it afforded them the time to strategise and come up with ways to exit the city safely. Carlos occasionally left the safety of the underground in order to scout around for civilians to rescue and he eventually bumped into Jill Valentine
, one of the new remaining S.T.A.R.S. members who was being pursued by an experimental B.O.W. named the Nemesis T-Type
After helping her escape the monster he took her to their underground base and the duo helped get the power back online and eventually they managed to get the trains running. Their destination was the Saint Michael’s Clock Tower, but in the way the Nemesis T-Type
appeared once again, tearing its way onto a rear train car - still in its mad pursuit of Jill. However, Carlos’ Captain Mikhail Viktor
bravely sacrificed himself by triggering a hand grenade which stunned the creature and also caused heavy damage to the train car. Once Carlos and Jill managed to escape the wrecked train car they quickly made their way to an evacuation helicopter which was waiting for them ahead - but miraculously the Nemesis T-Type
appeared once again and destroyed their escape route. The resulting explosion created a divide between Carlos and Jill and subsequently each had to press on separately.
Without Carlos to help, Jill soon found herself having to battle with a mutated a Nemesis T-Type
single handedly which was a monumental task - this ended in her receiving a t-Virus
infection from the beast. Carlos eventually reached her but she was already unconscious and the infection was beginning to take hold. He only had one option - he had intel on Dr Nathaniel Bard
who worked at the nearby Spencer Memorial Hospital. It has he who was working on a vaccine for the t-Virus
and he knew that just one of these vaccines could be used to save Jills life. He also had a desire to save the doctor so that his scientific research could continue.
Unfortunately when he reached Dr Bard he learned that he had been assassinated and his office ransacked - but he managed to find a dose and quickly brought it back to Jill - upon injecting her with the sample she began to recover quickly. Jill and Carlos awake to find that the US Government had planned to level the entire city by dropping a bomb on it within 24 hours. They quickly scrambled to the nearby NEST-2 facility which as an underground Umbrella research facility where B.O.W. research occurred but also the t-Virus
vaccine was developed and tested there - and they needed another sample of the vaccine in order to try and save everyone.
However the Nemesis T-Type
was still following - by this point it was heavily mutated as it had adapted various times due to all the damage it had sustained thus far. Everything came to a head when the beast was trapped in a waste disposal area which was littered with failed human experiments and t-Virus
infected organic material. Carlos unleashed hell on the beast - opening a valve which filled the entire area with an acid designed to break down all organic material and flush it away. The beast was seemingly destroyed by this and the two pressed on to obtain the vaccine and also attempt to prevent UBCS Sergeant Nikolai Zinoviev
from making his escape - by this point they learned that he had ulterior motives.
After Jill had one final showdown with what remained of the Nemesis T-Type
as it managed to recover somewhat from its destruction earlier, the two managed to reach a helipad on the roof and take control of a helicopter. Zinoviev was beaten to the punch by a hair and pleaded with the two to let him join them, even going as far as promising to reveal who he actually worked for in exchange for his safety.
The two flat out refused, leaving him to die in Raccoon City. They then left the area before its explosive destruction and went their separate ways.
Carlos returned to South America and ultimately lived in peace - not wanting to continually chase after Umbrella like many others before and after him. It’s clear he regrets what happened in Raccoon City as his mission was ultimately impossible - but at least he had his freedom.
As Resident Evil 3: Nemesis
and Resident Evil 3 (remake) have open-ended scenarios, the fate of Carlos is one of them. For instance, it is possible for Carlos to be killed.
Also, Carlos' hairstyle is customisable from the beginning in the remake - his hair changed drastically between the original game and the remake so a 'Classic' style is included.