He is the former Demon King, and Twilight's father. He also took in siblings Hades and Poseidon after they were reincarnated, and raised him alongside his own son. He is now in retirement, having handed down the reins of the demon kingdom to his son. His gigantic body is a representation of his mana, as evidenced by Oxenthree being left in a childlike form after Al Azif, the forbidden grimoire, suffers a case of rhinitis and has his magic go haywire, unable to control what spells it casts or whose mana to use for it.