After Batman attacked the gang at their headquarters, the Gotham City dump, in the Batmobile, the Mutant Leader called him a coward for using rubber bullets and for hiding in the Batmobile. This caused the Dark Knight to get out of the tank and fight the Mutant Leader, despite Alfred's protests. The Mutant brutally beat Batman, but just as he was about to kill him, Carrie Kelley, wearing a Robin outfit, provided a distraction, which was enough for Batman to subdue the brute. In prison, the mayor of Gotham tried to negotiate with the Mutant Leader, only to be murdered by him.
Later, following a plan conceived by Batman, Commissioner Gordon released him. Ending up near a sewer outlet, where his gang had assembled, the Leader is ambushed by Batman. Whereas during their first battle Batman tried to match the Leader physically, the second time he used his strategic mind to defeat him.
Following the Mutant Leader's defeat, the Mutant Gang split into several gangs, one of which was the Sons of Batman.
- Leadership - Able to raise a street gang into a militant force that threatened all of Gotham, the Mutant Leader has shown himself to be an effective leader.
- Peak Human Condition - Having just enough muscle not to slow him down, the Mutant Leader has displayed great strength and speed when fighting Batman, being able to over power the dark knight with ease in there first confrontation.
- Hand-to-Hand Combat (Advanced) - A savage fighter, the Mutant Leader was able to match an aged Batman blow for blow, and even out brawled him in their first fight. However, in their second bout, Batman was able to beat him using tactics and the environment.
- Diminished Intellect
- In the animated adaption of Batman: The Dark Knight Returns, Mutant Leader was voiced by Gary Anthony Williams.
- 5 Appearances of Mutant Leader (Earth-31)
- 7 Images featuring Mutant Leader (Earth-31)
- 2 Quotations by or about Mutant Leader (Earth-31)
- Character Gallery: Mutant Leader (Earth-31)