Dr. Harleen Quinzel, better known as Harley Quinn, is the secondary antagonist of the Batman: Arkham franchise overall, appearing as the secondary antagonist of the 2009 videogame Batman: Arkham Asylum and its sequel Batman: Arkham City. She also appears as a major antagonist in the 2015 sequel videogame Batman: Arkham Knight and its prequel episode Batgirl: A Matter of Family, and the main antagonist in Arkham City DLC: Harley Quinn's Revenge.