Joker (DCAU)

"What's so funny? I'll give you something to laugh about!"

- Joker

Jack Napier was once a lethal Mob enforcer before starting his own Criminal organization. A ruthless killer with no remorse and a dark sense of humor, his macabre mentality was further enhanced when, during a confrontation between the Batman, he somehow fell into a chemical vat, which turned his skin white, his hair green, his lips ruby red, and his eyes yellowish. A fate to be appauled by the sane majority, Jack grew mentally stronger with it, as well as crazier. He joined the rank of primary Mafia Bosses of Gotham, having more power than either Rupert Thorne or Stromwell, and rivaling other terrible crimelords many feared discussing, such as King Barlowe and the Penguin. Later he made the aquaintance of Harley Quinn, originally his psychiatrist and later his crazed henchwoman and squeeze. It is unknown as to whether she served as his underboss, but in his criminal syndicate she held considerable power as Joker's love interest. Together, theyon many occasions nearly killed the Batman, remaining among his top formidable opponents.