SPOILERS: Because of certain elements relating to Batman: Arkham Knight, we advise you to not look at the video above or read the rest of this post. It is recommended that you finished the game first to see anything here, but if you don’t care and just want to play as other characters in free roam, then go ahead and continue reading/watching.
Now that’s out of the way, let’s start. Modders Wastelander121 and MrJAG have worked together to make this mod available, a mod that allows you to play as any of the playable character in Batman: Arkham Knight in free roam mode. Play as Harley Quinn, Catwoman, Robbin, Nightwing, etc.
So here’s how to install the mod and play as those characters:
Download the mod first by going here.
Once download, keep opening the folders until you open the last one and see “BmInput.ini” copy and paste that file here (Steam\steamapps\common\Batman Arkham Knight\DLC\356474\Content\BmGame\Config).
Start a whole new game or continue your current save, but make sure to back up your save file.
To select one of the different characters you have to click the buttons from F1 to F12
F1: Red Hood (Need’s DLC)
F2: Harley (Need’s DLC)
F6: Bruce Wayne
F8: Com. Gordon
F10: Cop (from the diner)
F12: Joker FPS
Also, it’s noted by the modders that “If goons do not show up on the streets, then you need to restart from checkpoint to make them appear”.