The Man-Beast is one of many artificially evolved animals (Man-Beast being a wolf evolved into bipedal human-like form) created by the High Evolutionary. The High Evolutionary was attacked by Thor while Man-Beast was being altered, which caused for him to remain in the evolving solution too long; resulting in him being 'too perfect' and giving him a hatred of all forms of life.

Man-Beast turned on his creator and made his own army of Ani-men. Man-Beast and his army came into conflict with Thor and their creator and were defeated; being sent into deep space in a rocket. They later found their way back; invading the High Evolutionary's counter-earth and corrupting it. The High Evolutionary sent Adam Warlock after the Man-Beast and after a lengthy war that also brought in the Hulk from earth to fight alongside Warlock, the Man-Beast was beaten again.

Over the years since then, Man-Beast has fought Warlock and Thor on numerous other occasions; often fighting Thor alongside his ally the Bi-Beast.

The last time that the Man-Beast appeared, The High Evolutionary finally managed to de-evolve him back into a normal wolf with the help of Quicksilver.

On multiple occasions when the Man-Beast was battling Thor (after their initial encounters) and Warlock (with the Infinity Watch), Man-Beast was referring to himself as Karnivore.