Vengeance of the Dancing Gods — Jack L. Chalker

A Demon In The Cellar

Throckmorton P. Ruddygore, master wizard, had troubles again -- but this time, they were partly of his own making. He'd finally beaten-the Dark Baron, stripped him of all magical power, and exiled him from Husaquahr to Earth. But he hadn't counted on the Baron's using a computer there to create even more effective spells.

Of course, the Baron couldn't use those spells. But the forces of Hell soon sent him a second-rank wizard who could -- and a demon in the cellar to amplify the spells' power. They also worked a scam so that Ruddygore couldn't cross the Sea of Dreams to deal with the Baron directly And now the Baron was developing a scheme that would surely result in Armageddon before its time!

So once again Marge the fairy and foe the barbarian were called on to do the dirty work. They had to return to their home world and somehow stop the Baron -- if they could.

It looked hopeless, but...