He betrayed and killed Marcus, lured the S.T.A.R.S. teams into the mansion and nearly wiped them out, and even pretended to be dead to join Umbrella’s rival company.

Wesker was the one who sent Ada Wong to retrieve the G-virus and was involved in the incidents at Rockfort Island. He appears intent on gathering as much data as possible on viral weaponry. Since injecting himself with a virus during the events at the mansion, his power has grown far beyond that of a normal human being.