Another DLC, entitled "Harley Quinn's Revenge", adds a separate campaign, set after the events in the main story, which features both Batman and Robin as playable character, and sees them attempting to defeat a vengeful Harley Quinn, who has taken over the Joker's gang following his death.  "" is a prequel set five years before the events of "Arkham Asylum". It was developed by WB Games Montréal and written by "Assassin's Creed" and "Prince of Persia" writers Corey May and Dooma Wendschuh. The game is the first in the series to feature multiplayer gameplay, with that content developed by Splash Damage. The story follows a younger, less refined, and less experienced Batman, who has a bounty placed on his head by Black Mask, drawing eight of the world's deadliest assassins to Gotham City on Christmas Eve. Batman must defeat these assassins and bring Black Mask to justice, while also being hunted by the police, who see him as nothing but a dangerous vigilante, and having to foil the schemes of other villains taking advantage of the chaos, including the Joker, whom he encounters for the first time. "Arkham Origins" is set in downtown and east Gotham, which would later be transformed into Arkham City. Roger Craig Smith and Troy Baker voiced Batman and the Joker, respectively, replacing Conroy and Hamill from the previous two games. Like its predecessors, the game features DLC that adds extra challenges, as well as Bruce Wayne and Deathstroke as playable characters; the "Cold, Cold Heart" DLC adds an entirerly new campaign, set only a week after the events of the main story, on New Year's Eve, and depicts Batman's first encounter with Mr. Freeze.  "" is the sequel to "Arkham City"; it was developed once again by Rocksteady, and was released on the PlayStation 4, Xbox One and Windows on June 23, 2015. It is intended to be the final "Arkham" game by Rocksteady. Set nine months after "Arkham City", the game sees the return of the supervillain Scarecrow, who forces a citywide evacuation and unites several of Gotham City's greatest villains, including Penguin, Two-Face, Riddler, and Harley Quinn, to destroy Batman once and for all. Scarecrow is aided by the mysterious Arkham Knight, who desires revenge against Batman and seems to known much more about him than any individual the Dark Knight has faced so far. While attempting to stop Scarecrow and restore justice to Gotham with the help of his allies, Batman must also contend with an illness caused by the late Joker, which is physically and mentally transforming him into the Joker over time.