Jack Napier a.k.a The Joker was a professional criminal on Gotham City. He was the main character on Arkham Asylum TV series.
Jack Napier born on a netruel family but his father, John Napier, had a brain problem. His mother, Mira White, was a psychologist who worked on Arkham Asylum. When he was nine, his parents divorced and Jack lived with his father. His father humiliated Jack always.