M. Bison, known as Vega in Japan, is one of the main villains and primary bosses of the Street Fighter games.
His first chronological appearance is in Street Fighter Zero 2, as the head of an elusive criminal and military organization known as Shadaloo. Along with his aspirations for world conquest, M. Bison has been working on perfecting a lethal and deadly energy that will exponentially increase his fighting ability, an inherently evil energy he refers to as "Psycho Power".
Throughout the series, M. Bison occasionally attempts to increase his power by transferring his energy form into an artificially created physical body, thus increasing the limit of Psycho Power he can posses. His attempts were usually thwarted due to either the protagonist's actions destroyed his physical body, or that the intended new body rebelled against him.