The term U.B.C.S stands for Umbrella Biohazard Countermeasure Services from the Resident Evil
video games.They're owned by the Umbrella Corporation and are a different unit from the Umbrella Special Forces Unit (HUNK's unit, also known as the Umbrella Security Service) and specializes in rescue operations during biohazard outbreaks. Although they've been very successful in every operation, due to their high mortality rate the unit is comprised almost exclusively of convicted
war criminals and mercenaries for hire from around the world that
served their national militaries and joined the UBCS as an
alternative to capital punishment for any crimes they may have been caught committing. The unit is comprised of almost 120 operatives, divided between four platoons (with two or three squads per platoon).