Lisa Trevor is the daughter of George Trevor and Jessica Trevor. George was the architect that designed the original Arklay mountain mansion, the setting of Resident Evil (Biohazard). Lisa Trevor is a re-occurring enemy that first appears in the Gamecube remake of Resident Evil, most famously known for being completely invulnerable to damage, as well as seemingly having the face of her mother (or someone that looks like her mother) draped over her own head. By the time the player character meets Lisa, she has been severely mutated by a cocktail of viruses, sporting a severe hunchback and dendrites that sprout mostly from her back along with a hard-to-spot eye growing close to her left shoulder. She has also been driven entirely insane, abandoned to her fate in the mansion.
Lisa seems to be looking for her mother, Jessica, and will attack the player several times throughout the game with no provocation, swinging her manacled arms with a tremendous amount of force.
Lisa was originally infected with the Progenitor-B virus, while her mother was administered the Progenitor-A virus. While Jessica would not survive the A-type virus, Lisa proved that the B-strain was not as deadly, and served as a basis for creating the eventual famous T-Virus which would create the zombie outbreak in the mansion, and later spread to Raccoon City. Several other virus mutations were also injected into Lisa Trevor, and she would assist in giving birth to the G-Virus, one of the main plot devices in Resident Evil 2 (Biohazard 2).
Lisa's death in the game comes from her own hands, after the player opens the tomb of Jessica Trevor, proving to the tortured Lisa that her mother is in fact, dead. She jumps off into a seemingly bottomless pit, not to be seen from again during the game. Outside media states that Lisa survives that fall, a victim to her own prodigious toughness, but is eventually killed by Wesker, who takes her body to Umbrella, and their science team operating in Raccoon city, where William Birkin will later use her as the basis of creating the G-Virus.