Once a member of heaven, Asathanos was one of the early first to enter the halls of the afterlife where Adontis ruled. He was a master of fire and dabbled in different sorceries, flaunting his power to others without care. Eons passed and Asathanos grew stronger and stronger, his abilities honing until eventually he reached a point where his power was only surpassed by Adontis themself.
Foreseeing a conflict, Adontis cast Asathanos out from heaven with the charge to right the souls of those that had been led morally astray in life.
Asathanos now oversees the underworld, yet prefers to delegate his work to his servant Irvin. Instead the powerful bull opts to indulge in personal pleasures, luxuries, and parties - all of which his servant laments and despises. Asathanos chose Irvin to be his main source of power, transforming the deer into a powerful indestructible deity the bull affectionately nicknamed "Teeth".
In exchange for bountiful gold, Asathanos tasked Castline with the errand of feeding the immense monster he had created. Routinely Castline ferries mortals to an uncharted island where Teeth can rise to the mortal plane and feast. During one of these feasts Teeth was subdued by Octis, who had been brought in on Castline's ship after having fallen from heaven as banishment. Impressed and annoyed, Asathanos took Octis in and the pair proceeded to plot overthrowing Adontis for what he had done to them. In exchange for power and safety from Adontis' underlings, Octis hand-picks and raises the bull's army of demons. Little do they know that each of them ultimately plan to overthrow the other.
Wishing for greater power, Irvin approached Asathanos through a spirit board to gain what he sought. Unfortunately for Irvin, Asathanos turned him into his own personal steed, granting him a form more powerful than he could ever imagine but only accessible by Asathanos' will.