As “Suicide Squad” rolls into theaters, it’s hard to ignore the fact that Harley Quinn (Margot Robbie) is clearly designed to be the star. She’s the major focus of just about all of the trailers and her character’s design seems to be a big hit with those who want to watch the movie.

Who is Harley, though? Characters like The Joker, who is played by Jared Leto in “Suicide Squad,” have a long and storied comic book history but this incarnation of the Clown Prince of Crime has taken a backseat to Harley in the marketing — as has the rest of the Squad.

You may be surprised to find out that compared to most in the DC Comics universe, Harley Quinn is a relatively new character. Now, when we say young, she’s still 24 years old. When you consider there’s over 75 years of Batman stories though, she’s a fairly recent addition.

RELATED: ‘Suicide Squad’ gets roasted by critics, in 9 GIFs

And unlike most legendary comic book characters, Harley didn’t get her start in the pages of a graphic novel. She was actually born out of “Batman: The Animated Series,” in the episode “Joker’s Favor.” Created by Paul Dini and Bruce Timm, the character was initially meant to only have a small role as the Joker’s female sidekick.

However, it was the “Mad Love” comic in 1994 that allowed Dini and Timm delved into the character’s backstory. Dr. Harleen Quinzell was a psychiatrist at Arkham Asylum that fell in love with The Joker, helping him break out of the psychiatric hospital on more than one occasion.

It’s seeing him returned to Arkham battered after a battle with Batman that finally makes her snap, losing her mind and quitting her job to don a court jester costume and start to rule the world of villains with her beloved Mr. J.

RELATED: 5 things you can do this weekend instead of seeing ‘Suicide Squad’

This particular story was adapted to animated of “The New Batman Adventures,” which used the “Batman: The Animated Series” style and voice actors to tell the tale.

That’s not Harley’s only origin, though.

In the New 52 DC Comics Universe, Harley’s transformation from doctor to psychopath comes after The Joker throws her into a vat of chemicals, then rescues her from it. The dip in toxic sludge also accounts for her bleached skin, in addition to her unhinged mind.

RELATED: It’s a Tarantino fan’s dream come true with ‘Quentin Tarantino’s ‘Suicide Squad’

Based on trailers for “Suicide Squad,” this is the version of Harley’s origin that will play out on the big screen. Whether director David Ayer incorporated elements of the “Mad Love” story remains to be seen.

'Suicide Squad'

Beyond comics and cartoons, it’s worth noting this isn’t the first instance of a live-action Harley. Mia Sara played Harleen Quinzel on the short-lived “Birds of Prey,” which was set after the death of The Joker. Meanwhile, Harley made a quick cameo in Season 3 of “Arrow.” In the episode “Suicide Squad,” the character was briefly seen in an ARGUS detention facility. Actress Cassidy Alexa played the role, credited as “Deranged Squad Female.” However, she was voiced by Tara Strong — who voiced Harley in a variety of video games and the “DC Super Hero Girls” series.

So while Harley may not be as old as The Joker or Batman, she’s just as important a part of the DC Universe. And now, with Robbie taking her on as a live-action character, she’ll become even more entrenched in DC mythology.

“Suicide Squad” is in theaters Friday, Aug. 5.

Posted by:Chris E. Hayner

Chris E. Hayner is equal parts nerd, crazy person and coffee. He watches too much TV, knows more about pro wrestling than you do and remembers every single show from the TGIF lineup. You may have seen him as a pro-shark protester in "Sharknado 3." His eventual memoir will be called "You're Wrong, Here's Why..." TV words to live by: "I'm a firm believer that sometimes it's right to do the wrong thing."