"Harley Quinn, whose original name is Harleen Frances Quinzel, is a fictional DC Comics character who often appears as an enemy of Batman in the DC Universe. It was created by Paul Dini and Bruce Timm for the animated television series Batman: The Animated Series, first appearing in the episode "Joker's Favor" ("A Favor for the Joker"), which aired in September 1992. Despite Although Dini and Timm's original intention was for Harlequina to appear only in that particular episode, the positive reaction from audiences and critics was such that they included her in several other episodes of Batman: The Animated Series, culminating with the transition from Harlequin for the comic in September 1993 and her inclusion in the DC Universe in 1999 with the comic Batman: Harley Quinn. She is described as anti-heroine, today she belongs to the trinity of the most iconic female characters in the Gotham universe, alongside Cat Woman and Poison Ivy. The trio once formed a comic-book gang known as Gotham City Sirens, which had a 26-issue comic book series (2009-2011).

Arlequina's origins are told in the comic book "Mad Love" ("Crazy Love"), from February 1994, winner of the Eisner Prize. Its name was based on the harlequin, intending to be a pun on its original name, Harleen Quinzel. Harlequin is often accomplice and loving companion of the villain The Joker, whom she met while working as a psychiatrist at the Arkham Asylum, where the Joker was patient. And also counts in the film Suicide Squad and Birds of Prey.

The character was originally played by Arleen Sorkin in Batman: The Animated Series and in several other DC cartoons and animated films, although she was also played by Tara Strong and Hynden Walch. The first actress to play there was Mia Sara in the television series Birds of Prey. Arlequina debuted in theaters in 2016, in the film Esquadrão Suicida, being played by actress Margot Robbie. IGN ranked her at #45 on their list of the "100 Greatest Comics Villains of All Time". She was ranked as the #16 biggest villain of the past few years on the Comics Buyer's Guide list of "100 Sexiest Women in Comics.""