Billy Kitson was a promising young basketball player whose skills had won him a college scholarship. Unfortunately, a crippling accident ended his sports career, and an embittered Kitson turned to petty crime. Somehow, Kitson came to the attention of the rogue Egyptian god Seth, who genetically mutated Kitson into a super-strong man-bull, calling him Bison. Seth dispatched his agents Bison, Mongoose and Quicksand to steal a sample of the compound Inferno-42 from the intelligence agency SHIELD. In the course of this mission, Seth's agents battled Thunderstrike, SHIELD agent Alex DePaul, and hero-for-hire Luke Cage, who had been called in by Kitson's girlfriend, Shamari Asbery, in hopes of keeping Kitson out of trouble. During the battle, a conscience-stricken Kitson turned on his partners, defeating Quicksand and saving the life of DePaul, who let Bison go free in gratitude.
However, Kitson has continued his criminal career in hopes of amassing sufficient funds or resources to restore himself to normal, desperate to regain his humanity.
At some point, he was invited to join the Crimson Cowl's Masters of Evil, and he accepted, hoping to get rich through the Masters' blackmail scheme using global weather control. All Bison wanted was to get enough money for his own cure and reunite with Shimari. The team was defeated and apprehended by the Thunderbolts, and Kitson was remanded to custody.