LEGO Batman: Legacy of the Dark Knight – Building Mayhem with The Joker & Harley Quinn

XBox Wire says LEGO Batman: Legacy of the Dark Knight is getting the Mayhem Collection DLC on September 18 for Xbox Series X|S, shifting the focus from Batman’s hero journey to The Joker and Harley Quinn. The expansion is built as a love letter to Batman: The Animated Series, including 4:3 cutscenes and a stack of references across Batman TV, film, games, and comics.

The new story mission covers Harley’s origin from Dr. Harleen Quinzel to full-on villainy, with scenes set inside Arkham Asylum before the breakout and a Joker-and-Harley sing-along sendoff. There’s also a tribute to Arleen Sorkin in Gotham City via “Sorkin’s Gems,” which is a nice touch for fans and a reminder of how much character performance shapes long-running IP.

For gameplay, the DLC adds a villain hideout beneath Amusement Mile’s Funhouse, where players can decorate multiple areas and spend studs on permanent upgrades, props, and 30 new outfits. Mayhem Mode then pushes repeatable, time-limited runs across a locked-down North Island, mixing robbery, graffiti, vehicle theft, combat, and stud collection into a more arcade-like loop.

The other notable addition is Henchmaster, who lets players rescue Arkham inmates, train them, and assign them to a summonable crew. The Joker and Harley are also tuned to feel distinct from the main campaign, with faster, ranged gadget combat and freer movement that should matter to anyone watching how licensed games differentiate playable kits without breaking the core feel.