By any measure, Harley Quinn is one of DC Comics' most famous characters. Outside of the timeless iconic trio of Superman, Batman and Wonder Woman, Harley has been called the fourth pillar of the DC Universe by DC Co-Publisher and Chief Creative Officer Jim Lee.

While she might've started out as the Joker's sidekick on Batman: The Animated Series, she's gone through quite a few changes over the years. However, more than any other era, most of those changes took place during DC's New 52 relaunch. Now, we're taking a look back at how the once-evil villain evolved into the playful anti-heroine she is today.

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HARLEY QUINN'S ORIGIN

Harley Quinn's origins are revealed

Although Harley Quinn started off as a bit player in the Batman: The Animated Series episode "Joker's Favor," the character quickly became a favorite amongst the staff, leading creators Paul Dini and Bruce Timm to bring her into several different episodes. She was the Joker's girlfriend and loyal henchwoman who spoke with a distinctive Northeastern accent, as portrayed by the legendary Arleen Sorkin.

Dini and Timm went on to create a backstory for the character in the comic "Mad Love" (which would later be adapted for a The New Batman Adventures episode of the same name). In this story, she is revealed to be Harleen Quinzel, an overeager gymnast-turned-psychology-student. She wanted nothing more than to intern at Arkham Asylum, hoping to make a fortune off writing a tell-all book about the Joker's antics. However, in order to reach her goal of working at Arkham, she resorted to less than ethical means of passing her Psychology courses.

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While at Arkham, she fell in love with the Joker during their one-on-one sessions, breaking him out of the asylum on several occasions. During this phase of her life, she transformed herself from Harleen Quinzel into Harley Quinn, the Joker's dangerously loyal girlfriend.

After she was introduced in the comic book DC Universe, Harley's first solo series expanded on this period in her life, establishing that she had a dark fascination with the Joker before she ever interned at Arkham, deeming his work to be genius.

Harley Quinn

In the New 52's Suicide Squad run, Harley's Origin was slightly tweaked. Although she still worked at Arkham Asylum and fell to the Joker's influence, she seemed to be a driven psychiatrist. Her interest in the Joker is framed as a desire to help him and her naive personality was swapped for a more "no-nonsense" approach. Here, she doesn't buy everything the Joker tells her (like his numerous sob-story fake backstories) and instead, calls them false to his face.

In the New 52 origin, once the two fall in love and go on the run, the Joker inducts her into his ranks by tossing her into a vat of acid, mimicking his own "birth." Like the Joker, Harley's skin is permanently washed white. This is a stark difference to her original cartoon incarnation (and comic book appearances before the New 52) where Quinn was depicted as wearing white makeup.

HARLEY QUINN'S PERSONALITY

Harley Quinn

Before the New 52, the comic book Harley Quinn was more or less in line with the character of Batman: The Animated Series' depiction of Harley Quinn. She's naive, trusting to a fault and a bit childlike, but she also had an undeniably dangerous streak. She also wore an iconic red-and-black jester outfit that remained a visual remnant of her cartoony origins.

Rarely does Harley do anything out of the goodness of her heart, even though it's clear that she has a heart. Even when she does perform acts of kindness like saving a life or capturing a criminal, there's usually a pay-day involved. During the times she was separated from the Joker, Quinn was still fundamentally a villain, even forming her own gang called the Quinettes.

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In the New 52, she starts off as a villain with her work with the Suicide Squad. However, during Amanda Conner and Jimmy Palmiotti's Harley Quinn run, she went from being a villain to an anti-heroine. During this run, she also returned to her job as a psychiatrist (which, she is inexplicably no longer barred from practicing). She also works as a landlady and engages in vigilante work, armed with a new desire to clean up the streets of Coney Island. Additionally, she traded her classic costume for a more revealing but slightly more civilian costume. Her hair was also dyed in a split red/black combo.

Instead of bonding with villains as she once had, Conner and Palmiotti's Quinn sways them to the side of good. For example, by showing Egg Fu affection and offering him a place to live, he no longer felt the need to be a supervillain. Her solo New 52 series  also began to establish Quinn as somewhat of a Deadpool-esque figure, featuring her break the fourth wall and engaging in a series of wacky hijinks.

HARLEY QUINN'S RELATIONSHIPS

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Harley's relationship with the Joker was always tumultuous, complete with makeups and breakups galore. Although she had been known to stand up for herself and express her anger at the Joker, she never truly left him. Even during their breakups, Quinn would declare her independence (to no one's belief) but in the end, she wound up back with her "Puddin'."

When the New 52 took a more sinister approach to the Joker, it also applied that to Harley's relationship with him. In Suicide Squad, Quinn reacts poorly to the news of the Joker's apparent death, going on a killing spree to retrieve what was left of his body. When the Joker returned with a mutilated face, the two got into what is arguably the most intense and heated scuffle they've ever had, resulting in Harley declaring that he is no longer the man she loved. Thus, she announced her independence and has not returned to him since.

Besides the Joker, Harley Quinn was known to hang with the Gotham City Sirens, a team which consisted of Poison Ivy and Catwoman. She also had a brief friendship in Arkham with the Ventriloquist, Albert Wesker.

In the New 52 she was a member of the Suicide Squad, engaging in a bizarre relationship with Floyd Lawton. She still had her friendship with Posion Ivy though, and during Amanda Conner and Jimmy Palmiotti's run on Harley Quinn, the two were confirmed to be in a non-monogamous relationship. Conner and Palmiotti also gave her a new ensemble of friends in her vigilante group, The Gang of Harleys. She also befriended Egg Fu, a goat man, and a talking, burnt taxidermy beaver.

While the character of Harley Quinn is arguably unrecognizable when posed next to her former self, the New 52 transformed the character into what she is today. For better or worse, these changes look like they're here to stay for quite some time. The New 52 has set the template for Margot Robbie's version of the character, who's set to return to the big screen in next year's Birds of Prey. While the film will feature classic DC heroes like Black Canary and Huntress, the movie's unofficial full title, Birds of Prey (and the Fantabulous Emancipation of One Harley Quinn) makes it clear who the star of the show is.

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