He is a serial killer and a super villain, a madman who dresses as a clown and commits violent crimes, often known as Batman's most dangerous enemy, living and committing crimes in Gotham City, although most of his time is in Arkham Asylum.
He constantly adapts his personality to respond to the world around him, sometimes as a harmless charlatan and in other cases as a brutal mass murderer. Batman always has it in his sights.
