Oh, come on, Puddin!
Don’t you wanna rev up your ‘Harley’?
▶Harleen Frances Quinzel
▶July 20, 1990
▶Immunity to most toxins
▶The Queen of Gotham City
Harleen Frances Quinzel was born on July 20, 1990, in Gotham City, New Jersey, to Nicholas Quinzel, a Jewish-Catholic con artist, and Sharon Quinzel, a harsh housewife, and raised alongside her younger brother Barry, a slob with rock star dreams, in the custody of their mother after their father was arrested. As a model high school student, she achieved excellent grades in addition to her extreme gymnastics training and was awarded a full scholarship to Gotham State University, where she majored in psychiatry under Dr. Odin Markus. However, she began failing in her classes, so Markus met with her in her dorm room to help her outline what she believed was a good graduate thesis, centering around the belief that the circumstances under which a person disregards the rules of society were by committing a crime or falling in love. In order to defend it, Harleen had her mentor observe an independent experiment on the matter with herself and her boyfriend Guy Kopski, who developed a "think drink" to calm and center himself, as the test subjects.
This didn't go well for the two lovers, as Kopski's humor started to change so much that Harleen didn't laugh at any of his jokes while meeting with him, claiming to have driven through red lights in a stolen car after blackmailing Markus and possibly shooting him. She asked if she still loved her, but after noticing evidence of recently fired handgun, he ran out with it to shoot a homeless man he thought was Markus in the school gymnasium, then asked Harleen to help him shoot himself when she caught up with him. Although Kopski was found dead aftewards, it remained unknown if she helped pull the trigger or not, but it later became clear that Markus tampered with Kopski's "think drink" to counteract the stresses Harleen put him through. Harleen, however, believed that the situation was caused by chaos and that she would do anything to become involved with studying criminal psychiatry.
Harleen Frances Quinzel was once a highly intelligent, calm and compassionate young lady who worked at Arkham Asylum, before the Joker transformed her both mentally and physically into "Harley Quinn". Through the shock therapy and the Joker's manipulation, her mind and emotions were twisted and she was made into a homicidal, sadistic, child-like psychopath, who would use sexuality and her playful personality to achieve her goals or to entertain herself, usually harming others in the process. As of current time, she follows the Joker in whatever he demands of her, blindly smitten with the ruthless psychopath, affectionately referring to him as "Puddin".
Harley carries almost an innocent persona, wide-eyed and bright, finding humor in otherwise dark situations, much like Joker himself. After attacking Belle Reve guards and seriously injuring a couple before finally being restrained, she maniacally began giggling to herself in a sinister way, happy and pleased with how funny she found it, showing how fractured her psyche had become.