Wikipedia
Two-Face (Harvey Dent) is a fictional supervillain appearing in American comic books published by DC Comics, commonly as an adversary of the superhero Batman. The character was created by Bill Finger and Bob Kane and first appeared in Detective Comics #66 ( Aug. 1942). As one of Batman's most enduring enemies, Two-Face belongs to the collective of adversaries that make up his rogues gallery.
Once an upstanding Gotham City district attorney, Harvey Dent was driven insane after a mob boss threw acidic chemicals at him during a trial, hideously scarring the left side of his face. He subsequently adopted the "Two-Face" persona, becoming a criminal obsessed with duality. In later years, writers have portrayed Two-Face's obsession with chance and fate as the result of schizophrenia, bipolar disorder, and dissociative identity disorder. He obsessively makes all important decisions by flipping his former lucky charm, a two-headed coin which was damaged on one side by the acid as well. The modern version is established as having once been a personal friend and ally of James Gordon and Batman.
Two-Face was ranked #12 on IGN's list of the Top 100 Comic Book Villains of All Time. In the Batman film series, Billy Dee Williams portrayed Harvey Dent in Batman, and Tommy Lee Jones portrayed Two-Face in Batman Forever. The character has been voiced by Richard Moll in Batman: The Animated Series, and by Troy Baker in the Batman: Arkham video games, while Aaron Eckhart played both the district attorney and his villainous alter ego in The Dark Knight. Nicholas D'Agosto currently portrays Harvey Dent on the live-action TV series Gotham.