Harley Quinn was introduced as a psychologist at Arkham Asylum. It was stated she pursued psychology because she wanted to understand her broken family. she was assigned to treat Joker at the asylum. At first, she was intimidated by Joker, which led her to be her doctor. AS every session passed by, she kept falling in love with the Joker. She was so hopelessly in love with the Joker, that she even helped him to escape the asylum. Later on, she joined Joker in his evil plans and was passionately crazy about him. She fell in love with Joker, because of how broken he was from inside. She finally found someone who could understand her and make her feel complete.