Gotham Knights teased fans with a boss battle with one of the villains. The player is playing as Nightwing with Harley Quinn as the boss fight. These two fought in a video game before but not this brutal. Nightwing must capture Harley in the Return to Arkham DLC in the Arkham Knight, but they never engage in physical combat. There was a limitation on man-on-woman violence then. You just beat up her minions, and she will get arrested.