Another bizarrely inventive criminal from the minds of Kane and Finger, and member of the Batman rogues gallery is the super-shizofriend-turned foe Harvey Dent -aka Two-Face. Despite a rather confused origin in the Golden Age, the character has become a mainstay of the Batman franchise, appearing in all form s of media - print, video and film -into the present day. According to Wikipedia:
"Once Harvey Dent, District Attorney of Gotham City and an ally of Batman, he goes insane and becomes the crime boss Two-Face after the left half of his face is hideously disfigured; he chooses to bring about good or evil based upon the outcome of a coin flip."
Detective Comics #66 (1948)
Origin of Two-Face
Two-Face was one of many gimmick-focused comic book villains, plotting crimes
based around the number two, such as robbing Gotham Second National Bank at 2:00
on February 2. In his autobiography, Batman creator Bob Kane claims to
have been inspired by Robert Louis Stevenson's Strange Case of Dr Jekyll and
Mr Hyde, specifically the 1931 film Dr. Jekyll and Mr. Hyde
which he saw as a boy. Kane had not read the novel when he and Bill Finger
created Two-Face. Some inspiration was also derived from The Black Bat
whose origin story included being splashed with acid across his face."