The powerful sorcerer calling himself the Demon finds that his disciple has ran away to Doctor Strange. After he teleports him back, he keeps him prisoner to confront Strange. However despite his vast knowledge and mastery of the Dark Arts, the Demon is no match for Doctor Strange who defeats him in a mystical duel and then leaves him with a warning that he will be back for him if he does not renounce magic.

After Dr. Strange and the Ancient one have escaped an attack in Tibet by Mordo and his disciples, the Demon he has invaded Strange's sanctum. As he explores the place, Mordo's Demon senses a life force nearby but fails to confirm it.

Unable to contact Mordo, his disciple and his demon elaborate a plot with a third ally to place a regular bomb in Strange's retreat. Mordo's assassins capture the magician as he hurls the bomb away, but gets hit by the blast. In Mordo's absence, the self declared deputy assigns Mordo's demon the mission to probe the magician's mind. As he does so, Dr. Strange takes control of his and forces him to dissolve the spell that binds him. When Strange escapes, he reports to the deputy that he and Mordo's disciples failed to recapture him. Once the deputy has recovered Strange body, the prisoner uses his cloak and amulet and manages to defeat Mordo's evil trio one by one. After he forces the deputy to release his body of its bonds, Strange erases all memories of black magic from the trio's minds.