"Terror Tube" was the first of a planned series of one-offs inspired by popular music, called "Comic Rock" – in this case The Jam's "Going Underground".

These stories proved popular, prompting Mills and O'Neill to develop a regular series, Nemesis the Warlock, which combined the early high-concept science fiction with fantasy in the "sword and sorcery" mould.

Nemesis was revealed as a demonic alien with a horned dragon-like head based on the finned nose of his Blitzspear, fighting to protect aliens from Torquemada's genocidal tyranny, although his inhuman attitude and anarchic "Khaos" philosophy gave him an ambiguous morality; for example, in Book Five, "The Vengeance of Thoth", Nemesis is forced to hijack a bus full of children, which he then deliberately crashes, killing all on board as he escapes.

O'Neill's imaginative, grotesque art helped to establish the popularity of the series, but the efforts he put into creating it led to a low rate of productivity.

The series has been collected into a number of trade paperbacks, including: Nemesis the Warlock: The Death of Torquemada was released as a game made for the Commodore 64, Amstrad CPC and ZX Spectrum.

[2] Wizkids / NECA have released three figures of Nemesis the Warlock as part of their Heroclix collectable miniatures game (Rookie, Experienced and Veteran versions).