Once an upstanding Gotham City District Attorney, Harvey Dent is hideously scarred on the left side of his face after mob boss Sal Maroni throws acidic chemicals at him during a court trial. He subsequently goes insane and adopts the "Two-Face" persona, becoming a criminal obsessed with the number two, the concept of duality and the conflict between good and evil. 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.