Neil Fisher is the founding leader of TerraSave, previously an FBC operative who saved Natalia Korda during the Terragrigia incident. But he later revealed to be affiliated with Morgan Lansdale, seeking to revive the FBC following its disbandment when Lansdale's role in the Terragrigia's outbreak is exposed.
This motivates Neil to contact Alex Wesker, helping her organize the kidnapping of several TerraSave members for her selection experimentation with her T-Phobos virus in return for a vial of Albert Wesker's Uroboros virus to start his bioterrorist attack. After procuring Natalia for Alex, Neil is betrayed by Alex as she injects with the Urboros virus and sends him down to the lower levels of her tower to fight Claire Redfield and Moira Burton. The mutated Neil is killed during their fight when Moria, or Claire in the non-canon ending, shoots him in the head at point-blank range.