Underworld Unleashed was a multi-title American comic book crossover event released by DC Comics in 1995.
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.[1]
Plot
Neron dupes five of the Rogues who typically battle the Flash: Captain Boomerang, Captain Cold, Heat Wave, the Mirror Master, and the Weather Wizard. 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. He does not tell them that it will cost them their lives and unleash him onto the Earth. Lex Luthor, the Joker, Circe, Doctor Polaris, and Abra Kadabra become his Inner Council.
Neron sends magical candles to many supervillains. When they are all lit, they transport the villains to Neron's underworld realm. Many villains accept his offer, but some do not.