Wesker is an accomplished virologist notorious for his work with groups affiliated with the bio-weapons black market. As a senior researcher linked to the t-Virus Project as early as 1978, Wesker bore witness and in times shaped Umbrella's B.O.W. research. He officially left the company soon after the stall in the Tyrant Project, and began work as a spy, leading to a career in the United States Army and eventually with S.T.A.R.S. as its Captain. Wesker ultimately chose to betray Umbrella and work with other groups to steal its research data, benefiting from a mutation brought on by a prototype virus. Wesker was ultimately killed in March 2009 during a BSAA operation which uncovered his role in a doomsday project dubbed Uroboros.