The character you're referring to is
Two-Face from DC Comics. His real name is
Harvey Dent, and he was once a district attorney in Gotham City before a tragic event left him disfigured on one side of his face. After that, he developed a dual personality, one of which is a law-abiding, good person and the other is a ruthless, crime-driven villain.
Two-Face's defining trait is that he makes decisions based on the flip of a coin, which has one side scarred and the other clean. This coin symbolizes his struggle with his dual nature—he's torn between good and evil, with the coin deciding his fate.
He’s one of Batman’s iconic enemies, representing the theme of duality in human nature.