Harley Quinn
Dr. Harleen Frances Quinzel, also known as Harley Quinn (a pun on the word "harlequin"), first appeared in the Batman: The Animated Series episode "Joker's Favor", where she served as a humorous female sidekick to the Joker. In her first appearances she was depicted as a character completely devoted to the Joker, totally oblivious to his psychotic nature and obvious lack of affection for her; this characterization has remained more or less consistent throughout her subsequent appearances.