Harley Quinn

Harleen Quinzel, later and now known as Harley Quinn, is a former psychiatrist at Arkham Asylum turned criminal. She mentioned that during her childhood, her father became a conman and ruined her family, which lead her to become interested in extreme personalities. So she interned at Arkham and became their psychiatrist. While being toured through Arkham, she quickly found herself fascinated with The Joker, who began flirting with her.

After entering her office, she found a flower on her desk and immediately went to The Joker's cell. Joker admitted to putting the flower on her desk. She said that the guards would be interested to know he'd been out of his cell, to which he responded by saying if she was really going to tell she already would've. He said he liked what he had heard about her, and took a liking to her name. He said that it made him feel like there was someone there he share his secrets with.

3 weeks later, Harleen was interviewing The Joker, to which he told her a story about his abusive father. Harleen then began to fall in love with The Joker, to which she confessed to him about. After Joker escaped, she longed to see him again. But Batman came back the next day with Joker apprehended, which caused Harleen to have a mental breakdown. She donned a colorful jester outfit and blew up Joker's cell, becoming his new sidekick and girlfriend, Harley Quinn.

However, she later found out that everything The Joker had told her was a lie. Joker also frequently abused her, physically and mentally. He made several attempts on her life. Harley frequently tried to please Joker, but it was never good enough. Later on, she befriended Poison Ivy, who injected her with a toxin which made her immune to toxins and poisons. It also boosted her strength and speed.

She similarly befriended Catwoman, with the three of them making the group, the "Gotham Sirens". However, the group eventually dissolved due to Harley's inability to live without The Joker. However, Harley has since become her own woman, after she fell into the same vat of acid that had made The Joker who he is. She has been regularly caught by Batman and imprisoned, but she always escapes.

Harley has gone solo and has become her own criminal and woman, even helping the Suicide Squad on one occasion, however she hated the Squad. Harley now commits her own crimes and has her own thing going on.