Two-Face is one of the most famous Batman villains and he has a very distinctive disfigurement, by virtue of the fact that it splits his face straight down the middle. For much of his life, he was simply Harvey Dent - a good-looking District Attorney who had a clean-cut image and whose appearance had earned him the nickname "Apollo". However, he was disfigured in a sulphuric acid attack after the gangster Carmine Falcone hired the corrupt Assistant District Attorney Fields to carry out the barbaric assault. The event drove him to a life of crime, caused him to develop a multiple personality disorder and he became completely obsessed with duality - which is a good job, given the state of his visage. He's an expert marksman and a decent hand-to-hand fighter, but he relies on the flip of a coin to make all of his decisions for him.
