The Joker

Information The Joker is criminal in Gotham City that Jason Todd describes as "A weird motherfucker with a clown fetish".

He is responsible for 5000 murders in the city of Gotham he was born on August 1 1968 his birthname is unknown and he constantly makes up fake backstories to make the Doctors at St. Elizabeth Arkham Asylum for the criminally insane and that particularly worked on Dr Harleen Frances Quinzel who later became his girlfriend.

Origin (remember Joker said he doesn't even know his own origin so take this with a grain of salt)

The Joker's true name in this origin is Jack Napier he is a struggling comedian in the 1980's, he has a wife who is pregnant with a son and he is best friend's with a child version of Maltese prison inmate Bane tough Batman later interrogates Bane and Bane in his own words "I don't remember any Joker looking person before I met that stupid clown" anyhow Jack gets fired by the night club he works at so he turns to crime becoming a pawn for two more experienced criminals simply called Sal and Mitch, unbeknownst to Jack both Sal and Mitch work for the Red Hood crimegang and they're using jack as they're minion they rob a chemical plant where Jack used to work they later sell him out to James Gordon Sr and he fall's into a vat of chemicals scarring him for life.