Square Enix has only officially announced one world for Kingdom Hearts IV so far: a Coco-inspired Land of the Dead. That changed today, and not because of a trailer. A large-scale Steam API error pushed private achievement data for dozens of unreleased games into public view, and Kingdom Hearts 4 was among the biggest casualties.
The achievement database Exophase, which pulls data from Steam's backend API, suddenly found itself hosting achievement lists for games that were never supposed to be visible. The site's owner explained on a ResetEra thread that this appeared to be an error on Valve's end rather than a deliberate breach, noting that games without even a public name started appearing with full achievement sets over the course of about an hour.
Every world the leak points to
The Kingdom Hearts 4 achievement names paint a fairly clear picture of what Square Enix has been building. Here's the full list pulled from the leaked data:
That's 9 distinct worlds visible in the achievement data, with Coco already confirmed making the total count at least 10 areas in the game.
The Star Wars world is the headline
The Star Wars connection is the one fans will talk about most. Achievement names like "Desert Do-Gooder" and "May the Light Be with You" tie directly to the Galaxy Far, Far Away world, and players had already been speculating about a Star Wars crossover since the first Kingdom Hearts 4 trailer dropped. The leaked achievement names essentially close that debate.
Here's the thing: Star Wars has been a Disney property since 2012, and Kingdom Hearts has always treated the Disney catalog as fair game. A desert-based Star Wars world fits the series' pattern of picking one recognizable location from each franchise and building a contained story around it. Tatooine or Jakku seem like the most likely inspirations given the "Desert Do-Gooder" achievement name.
Familiar worlds returning alongside new ones
Two worlds on the list are Kingdom Hearts-original locations. Quadratum is the Shibuya-inspired setting introduced in Kingdom Hearts 3's epilogue and heavily featured in the Kingdom Hearts 4 reveal trailer. Scala ad Caelum appeared as a late-game location in Kingdom Hearts 3, so its return suggests it still has story relevance in the new entry.
The Toy Box world is interesting because Toy Story already appeared in Kingdom Hearts 3. Returning to the same franchise isn't unheard of in the series, but it would be a departure from the usual approach of cycling through new Disney properties each game.
Monochrome Origins is the most mysterious entry. The name suggests something built around the classic black-and-white Mickey Mouse cartoons, which would be a genuinely creative direction. Imagineer Planet reads as a nod to Disney's theme park division, which would also be a first for the series.
What Square Enix has actually said
Kingdom Hearts 4 co-director Tai Yasue and series creator Tetsuya Nomura stated at D23 2026 that the game is a "100% thing" for its late 2027 launch window, pushing back on any delay speculation. The game is targeting PS5, Xbox Series X/S, PC via Steam, and Nintendo Switch 2.
Square Enix has not commented on the leaked achievement data. Given that this appears to stem from a Valve-side API error rather than a deliberate leak, the studio is in an awkward position: the data is already public, but officially acknowledging it would amount to confirming spoilers the company clearly wasn't ready to share.
The broader leak context
Kingdom Hearts 4 wasn't the only game caught up in this. The same API error surfaced achievement data for Persona 6, an unannounced Steam port of Professor Layton vs. Phoenix Wright: Ace Attorney, an unannounced Telltale Games Walking Dead collection, and several other titles. The scale of the exposure suggests Valve pushed a configuration change that briefly made private achievement data accessible to any application hitting the API.
For an RPG like Kingdom Hearts 4, where world reveals are a major marketing beat, having 9 worlds surface this way is a significant spoiler. Square Enix had been drip-feeding information carefully, with Coco being the only world shown in any official capacity. That strategy is now considerably harder to execute.
With the late 2027 launch still over a year away, there's plenty of time for the studio to course-correct its marketing plan. Keep an eye on the Kingdom Hearts IV guides hub as more details surface closer to launch.
