Mortimer Kadaver was a hired assassin who worked in Gotham City. His first known associate was Derek Mitchell, but Kadaver eventually betrayed him, exposing him to the authorities in order to keep his share from their last blood contract. Kadaven continued his murderous enterprise until two years later, his actions drew the attention of the vigilante Batman. Around the same time, Mitchell had escaped prison and was transformed into the Corrosive Man, thanks to a freak accident. Kadaver was running his "business" as usual, when Batman and Mitchell came looking for him. His confrontation with the Corrosive Man left Kadaver a permanent hand-shaped burn scar on his forehead. Kadaver would've been killed by Mitchell, if Batman had not stopped him. The Dark Knight managed to stop the Corrosive Man and captured Kadaver for his criminal activities.
Kadaver was arrested and sent to the Gotham State Penitentiary, where he met Penguin and helped him fake his death as part of their master plan. Once outside, Penguin broke Kadaver out of prison and they started a criminal spree together. However, Kadaver forced himself into Penguin's gang and eventually, he was double-crossed by the man of a thousand umbrellas and he was shot. The police soon captured them both and Kadaver was returned to prison.
- Intimidation: Using his flair for the dramatic, Kadaver is adept in extorting and blackmailing people, using torture and scare tactics.
- 9 Appearances of Mortimer Kadaver (New Earth)
- 2 Images featuring Mortimer Kadaver (New Earth)
- 1 Quotations by or about Mortimer Kadaver (New Earth)
- Character Gallery: Mortimer Kadaver (New Earth)