The Magus was originally a future version of Adam Warlock created by the In-Betweener who came to believe that he was a god, leading his fanatical followers on a crusade to conquer the galaxy and eliminate all who were considered "impure". All non-humanoids and certain 'undesirables' such as trolls were to be exterminated and all others are to worship him or die. He formed the Universal Church of Truth to attain his whims by converting billions across the galaxy to his twisted beliefs.

His Black Knights protected the Church and his Grand Inquisitors hunted those who would oppose the Church and terminate them. Adam Warlock learned that the Magus was actually his darker self and it was his own responsibility to stop this madness. He was trapped by the Church and they attempted to convert him to their faith but his will proved too strong.

Warlock gained the assistance of Gamora and Pip the Troll. He was also aided by an unlikely ally, Thanos. Warlock was able to travel his own timeline and find himself before he was to become the Magus. He absorbed himself into the Soul Gem and erased the Magus from existence, and all knowledge of him and the damage done by his Church were eliminated from the universe.