Batman: Arkham - Ranking EVERY Villain Worst To Best

The sidekick and girlfriend - for want of a better word - of the Clown Prince of Crime, Harley's past as an accomplished psychiatrist does not make her any less insane in the present.

Harley Quinn appears in every main series Arkham game, with her role in the story getting bigger and bigger each time. Her relationship with the Joker plays out much like it does in the Animated Series - i.e. very unhealthily.

After his death, Harley goes through a dark and violent mourning phase, wearing a black veil and ditching her baseball bat for a good bit of firepower. But she's all back to normal by the time of Arkham Knight, her army of goons making her one of the most powerful criminals in Gotham.

The Harley Quinn story pack also explores the dichotomy between Harley Quinn and Dr. Harleen Quinzel, the rational part of her mind, giving her a whole new dimension on top of her increasingly domineering presence.