The main theme of Underworld Unleashed involved the new ruler of Hell, a demon-lord named Neron, offering first many of the DC Universe supervillains and then a number of the DC Universe superheroes various deals in exchange for their souls.

He promises them a chance to go down in history as five of the greatest villains if they each engage in a specific destructive act.

Lex Luthor, the Joker, Circe I, Doctor Polaris I and Abra Kadabra become his Inner Council.

The newly empowered villains are sent back to Earth to wreak havoc while Neron turns his attention to the superheroes.

Unable to even touch the offer, Neron's work is reversed: breaking that one deal also broke all his others.