Aaron Vricella

Aaron Vricella was the leader of a small group of anti-Umbrella ecoterrorists, whose mission was to bring the company down from the inside using spies. To this end, he recruited Matt Addison. Addison, however, felt that his sister Lisa would be a better choice, and Vricella agreed despite his misgivings. Although both of the Addison siblings died as a result of the venture, Vricella's fate remains unknown.

Fate
Because most of the world's population perishes as a result of the mass T-Virus outbreak depicted in Resident Evil: Extinction it can be assumed that Vricella was among the millions killed or zombified. However as this is never explicitly stated in either the films or their novels, this is pure speculation.