Harley Quinn (Arkhamverse)

A Blackgate Prison and Arkham Asylum psychiatrist assigned to treat the Joker, her first patient, Dr. Harleen Quinzel instead became fixated on her patient, believing herself to be in love with him. She helped him escape from confinement and took on her own criminal identity as Harley Quinn. Quinn is a violent and unpredictable felon whose only motivation, beyond general mayhem, is achieving the Joker’s approval. Because of his cruel and mercurial nature, this in some ways makes her just another one of his victims - albeit a very dangerous one.

Batman: Arkham Origins
Harleen interned at Blackgate Peninentiary and was finishing up her Psychiatry residency. Harleen Quinzel appeared when Joker got captured and was sent to Blackgate, where she performs a psychiatric profiling on him. During this session, Joker describes the encounter between him and Batman and states that it has changed the way he thought but never specifies that he's talking about the Batman. Harleen therefor thinks that Joker is talking about her, so she grows an affinity towards Joker.

She is then seen again at the Blackgate riot later that night where she is held hostage by a group of escaped prisoners. Batman quickly intervenes but she shows no hint of any form of gratitude towards her savior, nor does she show signs of shock from being almost killed. When Batman asks if she is alright, she replies "What's it to ya?". Harleen walks away from the Batman as he states that "You were almost killed." She then replies back "Eh, occupational hazard." and reveals that the Joker is located inside the panopticon, and that he is waiting for Batman's arrival.

Harleen is finally shown at the end of the main story escorting Joker to his cell with a group of guards.

Batman: Arkham Asylum
Sometime between the events on Christmas Eve and the Joker's takeover, Harleen Quinzel went as far as to become Harley Quinn for her love for Joker and joined him in his criminal pursuits. Years into the future, she presumably got herself arrested to get incarcerated at Arkham before Joker came in order to set everything up.

Harley made her way to Bane 's holding room in order to sedate him. The reason for this was to keep him quiet when the "visitors" arrive. She then went and sat in the security control room, watching the monitors and awaiting the Joker's arrival for incarceration as her signal.

Whilst Batman was escorting the Joker through a Intensive Care unit of Arkham Asylum, Harley was already in the security control room. As the Joker broke free, she opened the adjacent security field allowing him to escape Batman and implement his takeover of Arkham. The Joker then proceeded to release all his followers from their cells to attack Batman. Harley then took Warden Quincy Sharp hostage, taking possession of his decorative cane as well as wearing his warden identification card, and contacted Batman via monitor. She claimed that the Joker was now in charge of the island and she was substituting for Sharp as warden. She also told Batman that Joker was having a homecoming party with Batman as the guest of honor. Batman gave Harley one chance to surrender, which she refused before smashing her monitor with Sharp's cane, cutting off the feed. When Batman made his way to the elevator shaft, Harley appeared, stating that the Joker didn't need to see Batman just yet. She proceeded to blow up the elevator cord, causing the elevator to crash to the floor below and sending herself to the top, nearly killing a security guard had Batman not saved him. Harley then regrouped with Frank Boles, who had taken Gordon hostage. She and Boles proceeded to secure the front entrance of the Intensive Treatment Center and fight off the guards with an army of Blackgate prisoners. After Boles, who had outlived his usefulness, had been disposed of by the Joker, Harley took Gordon and carried on without him.

Quinn, with Gordon, made her way to the Batmobile first, ordering her goons to break into it. She then proceeded to the Medical Center and sat in the main entrance with Gordon tied to a bench by her, relaxing during her "me time". Batman eventually tracked Gordon to the entrance and found Harley humming to herself, but was unable to reach her due to a energy security gate blocking her. Spotting Batman as he walked in, she told him to scram. He asked where Gordon was, to which she replied "Wouldn't you like to know?." Gordon then shouted to Batman, and Harley told him to shut up and threw a glass mug at him. He called Harley a "crazy bitch", and Joker contacted Harley via monitor. He yelled at her, and she squealed in a startled tone. Joker asked why Batman was in the Medical Center, as it was "too early." Harley apologized and kissed Joker through the monitor, asking him not to be angry with her. He then said "You little minx! I could never stay mad at you!" and turned off the monitor. Harley then said that Batman needed to find another way in and bid him farewell, cartwheeling out of the room. She took Gordon to Bane's holding area, given orders by the Joker to kill Gordon if anyone spotted Batman nearby. Batman followed a trail of tobacco left by Gordon to the Medical wing, defeating Harley by crashing through the glass ceiling above her, and rescuing Gordon. Harley, however, evaded capture after Bane attacked Batman. Harley made her way back to Warden Sharp and followed Batman to Arkham Mansion. She came across Batman stunned on the floor after the large explosion in the Warden's office killed Dr. Young, making an empty remark of pity and expressing how Joker "hates a squealer." She then took the tape off of Sharp's mouth and smacked him around with his cane, accidentally breaking off the jewel tip of it after aggressively striking him on the head. She left a few goons to take Batman to 'the party', but he defeated them and used the Warden's DNA traces from his severed cane tip to follow Quinn. She then made her way to the Penitentiary with the Warden, forcing him to read a variety of threatening statements written by Joker over Arkham's intercom system and torturing him when he hesitated and insulted her.

After locating the Warden locked up in an abandoned control room, Batman saw Harley on a nearby monitor, passing Poison Ivy's cell. Despite not being on the 'party list', Poison Ivy convinced Harley to let her free. As Ivy happily strode away and blew Harley a kiss, Harley sighed and said "She's a good kid."

Batman followed Harley and surpassed a variety of her traps until there were few goons left standing. Harley even electrified the pacification system on the asylum floor to the maximum power to stop his advance, electrocuting a security guard as a demonstration. Batman eventually got past this obstacle and fought his way through the remaining Blackgate convicts and escaped mental patients before the fifteen remaining thugs attacked Batman in the Extreme Incarceration cell block. After they were defeated, The Joker decided that Harley had failed him, removing Harley from the 'party list', much to her annoyance. Out of anger, Harley used her acrobatic skills to attack Batman but was defeated with ease. Batman took Harley's 'party list' and scanned her hand, acquiring her fingerprints Batman locked up Harley in an adjacent cell, with Harley accidentally revealing the Joker's location and claiming he would rescue her. Batman left Harley crying alone in her cell. After walking into a nearby room to examine a glowing green trophy placed there by Riddler, Batman became trapped inside after the a set of bars slid over the doorway. Harley then taunted him: "The stupid bat has fallen into my trap!", suggesting that she had Riddler place the trophy in there to trap him. Batman used his Explosive Gel to destroy the wall above the cell and climbed out back into the cell block, prompting a shocked Quinn to give a violent start and demand, "What? How did you get out of there!?"

It can be safely assumed that Quinn was escorted back to her usual cell by the surviving Arkham staff upon the Joker's final defeat.

Batman: Arkham City
Six Month's later, Harley has been incarcerated in a high security cell, believing the rampant rumors that the Joker is dying to be false. However her hopes are soon shattered when she overhears a conversation between some guards not only confirming the Joker's short lifespan but also a conspiracy to have him killed. With this she kills and replaces one of the guards planning to kill Joker and rescues him right in the middle of the attempt on his life.

In another issue, it is shown she had a great deal of jealousy for Scarface, who was much more entertaining to the Joker. "By accident", she dropped the dummy into a furnace and apologized. Another copy of the dummy was brought out and Joker used it to point at Harley as if to say "I'm watching you" showing he's enjoying messing with her mind.

Harley first appears in the Church, with the gang keeping hostages. As Batman enters, she charges, backflipping towards him. However, Batman's reply is to contemptuously throw her aside as before. The thugs say "let the lady go,bat freak or these people all get a bullet in their heads", threaten to shoot him if he makes another move and Harley agrees saying "i think you should do what he says,It would be a shame to get blood all over my nice new outfit!,what do you think bat brain like, well what am i saying of you do who wouldn't".As she's talking to batman, Harley tells him "so anyway here's the deal,Mr.J is not up to a visit right now he's not feeling himself.Well actually he was earlier but that's not what i meant, he's doing so good with that a idiot of course didn't help.I i've seen more smarts than these bozos.I got to run boys,if he tries anything funny kill him".Mocking batman she walked towards the door,looked at batman and blew him a kiss,walked out the door,and drove to the sionis steel mill.

Harley's voice is heard sometimes over the loudspeaker,sometimes she would say "listen up dumbasses and listen carefully,as you all know mr.J is....he's...he's not himself and the last thing he needs is a so called super heroe coming in here,stopping his recopperation.That's where you come in morons,you need to protect the steel mill,prorect with your life,because if you fail i'll make sure your miserable lives don't mean zip.Get good." at the Sionis Steel Mill, telling the goons to keep Batman out or else. When Batman enters the main hall, she tosses down a young doctor who failed to help Joker and calls in the one armed thug as entertainment for the clowns. As Batman rushes to save the doctor, at the last second as Baker is going to get crushed, Harley tells him to stop, saying Joker wants her to suffer a bit more while demanding the thugs go capture Mr. Freeze, who apparently has a cure for the Joker. Baker is dragged out and Batman makes his way out. When in the main area, Harley angrily yells down at him saying "what the hell are you doing here,your supposed to be dead.Well there's no way your going to get mr.J,we're safe and sound up here,you can just stay down there and BURN!!", closing the metal doors of the foremans office. As Batman walks away, through the walls, you hear Harley exclaim "Oh Mr. J! You look perfect! ...Oh....its not really you, is it?" and Joker shushes her.

After finding and saving Stacy, Batman breaks through the doors of the facility with a crane hook, but is stopped by Mr. Hammer as Harley angrily tells Batman to leave Mr. J alone. "what's wrong with you bman, you come into mr.J's home and start smashong it into pieces,don't you know he's sick?" After Batman beats Hammer and several other thugs, he hears Harley scream in anguish as he grapples up, finding her by an apparently dead Joker. Shoving her aside and scanning Joker, she asks why he's so mean, leaving him open to a knock out gas attack of Joker, who tells him "You fell for the old fake Joker gag!" As Batman reels from the gas, Harley approaches with a baseball bat, saying "Batter up!" and knocking him out.

As Batman awakens, Harley reaches for his mask, but Joker tells her"get back here Harley". Harley complains"but i want to know who he is sweety", but Joker makes it clear"no one's who you think they are my dear,so why spoil the fun" and she sullenly waits while he talks to Batman. Later, the cure for the Titan disease is stolen by Harley and Batman chases after her. However, when he finds her in the Sionis Steel Mill, she is taped to a support pole and gagged with duct tape, no cure in sight. When you pull the tape off, she angrily complains, saying she won't talk, especially about a set of Freeze's stuff Joker stashed in the boiler room. She is later revealed to have been tied up by Taila, who stole the cure back from her.

Later, Harley and his thugs were outside waiting for Joker to become immortal,but they find batman carrying Joker's dead body and the horrified Harley Quinn falls to her knees,mourns his death,and plans to avenge the Joker.

In the game when you're in the Joker's hideout, Harley's old  outfit from Arkham asylum hangs on a pole. Below the outfit is a positive pregnancy test that  can be seen. At the end credits Harley sings "Hush little baby don't say word, momma's gonna kill for you the whole damn world", implying that she may be pregnant with the Joker's child, or that she has already given birth.

Harley Quinn's Revenge
After the Joker's death, Quinn became even more psychotic and fierce, managing to strike fear and respect into the Joker's old henchmen, who had previously seen her as a useless bimbo. She is shown to be constantly mourning, donning a darker outfit and frequently crying. Her bursts of anxiety lead her to kill henchman at random and instead of becoming annoyed at the henchmen when they make a pass at her (as she had usually done prior to Joker's death) she becomes infuriated and murderous, declaring that they should not try to seduce "a widow."

Weeks after the Arkham incident, Harley breaks out of the holding facility she's in and hatches a plan to kill Batman and avenge the Joker. She reforms the Joker's old gang and despite initially meeting resistance from Mr. J's old crew, her new, more vicious and more psychotic personality convinces them to join her. As part of her plan, Quinn kidnaps several police officers and locks them away in the old Steel Mill. Batman gets sent in to save the hostages but is captured by Quinn, who locks him in a giant statue of the Joker inside the shrine she'd built for him.

Days later, Robin went into the Steel Mill to look for his mentor. After finding his discarded utility belt in the smelting chamber, he goes to the Shipyard, where Quinn is holed up. There, he finds Batman in the Joker statue and discovers that he needs Harley's access key to free him. Robin finds Quinn and defeats her henchmen before fighting her. Though Quinn proves to be a tricky adversary, Robin ultimately defeats her and takes away her access key before leaving her hanging upside down from a catwalk.

After Robin saves Batman, Quinn unveils her plan: a suicidal bombing of the Shipyard aimed at killing Batman and Robin and "reuniting her with dear Mr. J." She triggers the explosives but Batman manages to defuse them before they go off, while Robin frees the captured policemen. A furious Quinn reveals her failsafe; a hidden bomb in the Joker statue. The mad woman sets it off to kill herself and Batman but fails when the Dark Knight leaps out of a window, carrying her with him.

A tearful Harley yells at Batman that he should have left her behind but Batman ignores her as he realizes that Robin is nowhere to be seen. Suddenly elated that she managed to kill Robin, Harley mockingly tells Batman that now he knows how she feels before trying to stab him in the head with a concealed dagger. She fails, since Robin appears and knocks the dagger out of her hands with a shuriken. Harley Quinn is subsequently arrested and taken back into custody.

Inside the Manager's office in the Steel Mill, a crib with the Scarface puppet inside it can be found. Scarface is dressed up and painted like a baby Joker and he has a positive pregnancy test in front of him. Surrounding the crib, however, are a dozen negative pregnancy tests. A box is lying around nearby which reveals that some pregnancy tests can show false positives. It is implied that the discovery that she was not pregnant with Joker's child is what finally drove Harley over the edge and made her more vicious.