Some TMNT stuff really isn't for little kids.
Harvey Dent was the District Attorney of Gotham City before an assault left him disfigured and demented, leading him to take the name Two-Face and administer compassion or terror at the flip of a coin.
Batman/Teenage Mutant Ninja Turtles
Two-Face was amongst the Arkham Asylum inmates who was mutated by the Shredder and Ra's al Ghul. He was changed into a mutant baboon, with different colored and styled hair to reflect his two personalities.
During the final battle, he was among the combatants whom Splinter fought, and was defeated. It was later confirmed that he would revert back to normal in a week's time.