Chaos in Gotham: Details of the First Major DLC for LEGO Batman: Legacy of the Dark Knight Revealed

Not much is officially known about the first major expansion for LEGO Batman: Legacy of the Dark Knight. According to the Steam page, the “Chaos Collection” expansion will be released in September 2026 and will be available as part of the deluxe edition or as a standalone DLC.

The developers promised a new story mission where Joker and Harley Quinn will have to fight their way out of Arkham Asylum, as well as a separate “Chaos” mode where the heroes will wreak havoc on the streets of Gotham.

However, more precise details surfaced thanks to datamining. Insider X0XLEAK, who previously specialized in accurate leaks for Marvel Rivals, published a massive leak of hidden expansion files.

According to his data, in “Chaos” mode, Harley Quinn and Joker will confront the government organization A.R.G.U.S. and members of the Suicide Squad. The files found 12 canonical DC characters, including Rick Flag, King Shark, Deadshot, Captain Boomerang, Bronze Tiger, Deathstroke, and Katana.

Earlier, the dataminer also shared other gameplay details. Harley Quinn will get her pet hyenas Bud and Lou. The “Chaos” mode will have its own currency and seven to nine main missions with bonus challenges, for completing which commemorative badges will be awarded. A new hub location will also appear in the game — the “Chaos Hideout,” where a challenge board and a clothing store will be located.

The clothing store will be added for a reason: according to the insider, Joker and Harley will receive more than 40 outfits. Among them will be outfits based on Injustice 2, Arthur Fleck's costume from Todd Phillips' film “Joker,” and Harley's look from the Absolute Batman comic line.