Voice-actor: Diedrich Bader.
Appearances: The Breakout, The Batman/Superman Story Part One, and What Goes Up.
The Number One is the name given to the second-in-command of Black Mask's crime organization.
After Black Mask was locked up, the first Number One managed to capture the Batman and take away his utility belt. Number One led Black Mask's henchmen during an attempt to free him. After breaking Black Mask free, Black Mask congratulated Number One and later took out a gun from Number One's coat and shocked him. Black Mask later chose one of his henchmen at random and decided to make him the new Number One. He popped up on the news as one of the villains captured by Rumor and was seen with the rest of Black Mask's henchmen and other villains when it came to luring Superman to their trap, which might indicate he was able to convince Black Mask his services were still useful.
A new Number One was seen when the Shadow Thief rescued Black Mask out of Arkham Asylum, and held up the police when the robbery of the meteor went wrong. He questioned on how Black Mask was going to use the Nth Element on the Gem Depository, as it was practically a fortress. Black Mask exposed him to it and was up on the ceiling. When Number One understood Black Mask's plan, Black Mask sent him flying upward toward the atmosphere and elected an eye patch-wearing female as his new Number One.
The female Number One was appointed second-in-command for being one the Organization's best elites. She is notoriously bombarding Warhawk from a war helicopter but is ultimately stopped when Hawkman destroys the chopper. The female Number One managed to survive with a parachute.