Dr Harleen Quinzell Is a normal lady in gotham who becomes a phyciatrist at Gothams prison, Arkham Aylum. She meets the Joker and becomes his phyciatrist. After acouple of sessions she falls inlove with him. She Breaks him out of Arkham and reinvents herself as The One and Onley Harley quinn. She currently runs along side The Joker as his houmourus but unpredicdable sidekick.