Harley Quinn

Harley Quinn is one of the major characters from the DC Comics.

Harleen Quinzel was a psychiatric resident at Arkham Asylum, where she met the incarcerated Joker. Falling in love with her patient, she conspired to break him out of prison and eventually became his lover and loyal sidekick, Harley Quinn.

Personality
Details of Harley's character vary depending on the incarnation, but most versions have an obsessive infatuation with the Joker whom she nicknames "Mistah J" or "Puddin'". Blindly loyal to the Clown Prince of Crime, Harley is often depicted as a victim of physical, verbal and mental abuse, eroding her sanity and resulting in a sociopathic madwoman. Occasionally, she shows signs that she knows her obsession with the Joker is unhealthy, but only a few incarnations have been able to fully break away from him.

Bubbly, energetic, and charming, Harley often hides her demented mind behind a childish exterior, which she can combine with the flirtatious demeanor of a woman who is aware of her good looks and will use them to get what she wants. She is also much more intelligent than she lets on, often causing friend and foe alike to underestimate her — in the Mad Love storyline, she came closer to killing Batman than the Joker ever did — and some incarnations even have a genius level IQ, despite her insanity. Her training as a psychiatrist gives her a knack for getting into people's heads. In addition to being a skilled manipulator, she's prone to explosive fits of rage and has a violent streak that almost rivals that of the Joker himself. Indeed, the very first incarnation of Harley could even intimidate him when she was angry, although later incarnations are often submissive and put up with his abuse out of a misplaced sense of loyalty.

Unlike most versions of the Joker however, most of Harley's incarnations do possess a softer side and are capable of genuinely caring about others. She treats her pet hyenas, Bud and Lou, like her own children, calling them her "babies", and genuinely loves Poison Ivy, whom she often nicknames "Red" or "Pammy". The nature of their love depends on the incarnation, with some being portrayed as lovers, others as close friends, and a few even behave like family members, with Ivy often acting like a big sister or a mother to the more immature Harley. Harley can also be very loyal to people she cares about, but at the same time she struggles with an innate selfishness and a sense of dependence on others. Her loyalty to people like Ivy rarely surpasses her loyalty to the Joker. However, a few incarnations have realized that her loyalty was misplaced, and managed to redirected it towards people who deserve it. On several occasions, she has sided with Batman and even became one of his most trusted allies in the Injustice series.

While most versions of Harley have attempted to leave her life of crime behind at least once, only a few have succeeded. Those that have can rarely escape from her destructive past completely. Harley's grandchildren followed in her footsteps in Return of the Joker and after Joker's death in the Injustice series, he was revealed to still be her greatest fear when she was exposed to Scarecrow's fear gas.

Abilities
Harley didn't start out with any actual powers. However, after a failed attempt by the Joker to blow her up in a rocket she was given a "potion" by her friend Poison Ivy. This enhanced her strength, speed, and agility, gave her an immunity to toxins, and a small healing factor (though this seems to vary -- later in her solo series she was shown to be able to heal from gunshot wounds in a matter of seconds as soon as the bullet was removed). She is also an impressive fighter, often using acrobatics that she had trained in as a young woman. She uses many odd and unique weapons and gadgets, such as her traditional mallet, or a large pistol with a large cork in it. Both of these she uses to surprising efficiency and they end up being more useful than they would seem on the outside.

Poison Ivy gave Harley a strange brew that increases her strength and speed. She doesn't have powers far beyond those of mortal man but she really has more physical strength than any Olympic athlete. She is able to put any man to the floor in only two punches or one kick. Her legs seem really powerful, she manages to jump very high without effort -- this, coupled with her prodigious gymnastic skills, makes her an incredibly acrobatic and "bouncy" threat in combat, adding to her momentum with pendulous weapons such as her hammer.

Additionally, Harley is a master of disguise and often employs elaborate disguises as part of her crimes. On various occasions she has disguised herself as a member of a rocker's entourage, a secretary, a film executive, a police officer, an opera singer, a flight attendant and a prison guard, often mugging or tying up the victims she replaced. More significantly, Harley posed as a romance columnist named Dr. Holly Chance for an extended period, and later took on the identity of Dr. Jessica Seaborn when she decided to become a therapist once again.

Trivia

 * Harley implies that she may have schizophrenia, as she claims to hear voices; she also implies that she sees things that aren't really around as she mentions being "off her meds" upon seeing the Enchantress's magical superweapon.
 * In promoting the film, this version of Harley Quinn was added to the mobile version of DC's video game Injustice: Gods Among Us. She, alongside the Joker, were added alongside Deadshot to the game, while members of Suicide Squad were also added as "gear cards".
 * Harley claims to be unable to swim.
 * According to her mug shot, she was caught by Batman on October 13, 2014.
 * According to Zach Snyder, the death of Robin takes place 10 before the events of Batman v Superman: Dawn of Justice, which takes place in 2015, which places Jason's death in 2005. And in Suicide Squad, it is revealed that Harley was involved with Robin's murder, however Harley was born in 1990, which would have made her 15 at time of Robin's murder.