Magnus is a magic user born in the 6th century. He was turned down as an apprentice by Merlin but got accepted by Morgan LeFay. She became both his mentor and his lover. He was disturbed by her hatred for her own brother,Arthur, but chose to overlook it. Until Morgan turned to the Darkhold and Chthon as sources for her spells. Magnus realized her hatred had corrupted her and ended the affair.
Charles Magnus was created by Marv Wolfman and Carmine Infantino and first appeared in Spider-Woman Vol.1 issue 2 (1978).
Major Story Arcs
While he remained with the Darkholders for a while, Magnus' cause was actually to steal and hide it away. He managed to accomplish the goal and sealed the tome in the Isle of Wight, protected by elaborate spells. Magnus himself was on the run, fleeing the vengeance of Morgan. Predicting she could kill him, Magnus performed a ritual preventing his spirit from passing on to other planes of existence. During a session of astral projection, Morgan found and slew his body. But his spirit remained bound to Earth.
The Drew Legacy
In 1932, renewed activity by Chthon attracted the attention of Magnus' spirit. Unable to act without a body, Magnus possessed that of Jonathan Drew. He tried to convince Drew's partner Edgar Wyndham (Great Evolutionary) to abandon Wundagore Mountain. But Wyndham held no belief in the supernatural and ignored the warning. He did however convince Wyndham to train his New Men as the Knights of Wundagore. The cause was simple, noble spirits could resist the corruption of Chthon. Magnus was satisfied and vacated Drew's body.
Having had a taste of life again, Magnus took to possessing other bodies. Decades later he introduced himself to Jessica Drew ( Spider-Woman). She was the daughter of Jonathon and had been raised in Wundagore, infested with the energies of Chthon. An infestation which called the attention of Morgan and caused the enmity of the two women. Magnus and Jessica met in London, traveled together and settled in Los Angeles.
He eventually left his current body but continued checking on Jessica and helping at the hour of her need, having fallen in love with her. However when Jessica was dying due to a spell by Morgan, Magnus could only revive her by sacrificing his own existence. After fourteen centuries on Earth, Magnus was finally dead.