A race of winged bird-like creatures once inhabited earth, but went into seclusion in a floating city 80 miles above the earth, hidden in a cloud when humanity became the dominate species. When the Avian race decided to go into hibernation for their survival, they created the Bi-Beast to become their Sky Island's security guard and protect it from harm in their absence. After years in isolated loneliness, Bi-Beast went mad, and tried to kidnap Betty Ross (Who the lower brain was attracted to), who at the time had been transformed into the winged gamma monster, Harpy. It also attempted to kidnap Bruce Banner (An idea of the upper brain) to repair some of the Sky Island's technology that began to fail. After Hulk followed the Bi-Beast to the Sky Island, a brutal battle ensued. Following the confrontation with the Sky Island's protector, Bruce Banner was able to use the Sky Island's technology to cure Betty of her mutation. Unknown to the Bi-Beast, MODOK had followed the Hulk in order to kill him. Upon reaching the Sky Island, MODOK decided to conquer the city for himself. To stop MODOK's mad scheme, Bi-Beast decided to destroy his home rather than let MODOK take it over.

Later, he took control of the S.H.I.E.L.D. Helicarrier and attempted to stop the Hulk with it's lazer system. After yet another defeat, Bi-Beast began capturing ships to melt down and create another Sky Island, but this time he met defeat at the hands of the mighty Thor.

The lower brain became in love with the Jade Giantress, She-Hulk, but she turned him down. Bi-Beast also came into conflict with the Defenders, but is still at large after his defeat.