Kingdom Hearts 4 references a bit of OG lore so obscure I wouldn't have blamed Tetsuya Nomura for forgetting it
Kingdom Hearts lore is extensive, convoluted, and confusing. I don't mean that as a dig – I am a Metal Gear fan, after all – but even after playing every game in the series, I've still got to read a half-dozen wiki pages and watch a few lore videos before I start remembering the specifics of any given plot beat. That's why I'm so impressed that Tetsuya Nomura and the rest of the devs have managed to remember a small, but key detail about Heartless behavior in Kingdom Hearts 4.
The first Disney world announced for Kingdom Hearts 4 is Pixar's Coco, In the recent D23 trailer, we see a pair of Heartless emerge and start creeping toward the film's protagonist, Miguel, who is the only living person in the vicinity – they completely ignore the other denizens of the Land of the Dead.
A couple of days after that trailer debuted, a Kingdom Hearts fan called Noir LilBomber tweeted a theory: "One thing me and my friends noticed in the kingdom hearts 4 trailer is that the heartless only appear to react to Miguel and not the other characters. This is in line with the Ansem report from KH1 that stated the heartless only react to LIVING test subjects."
One thing me and my friends noticed in the kingdom hearts 4 trailer is that the heartless only appear to react to Miguel and not the other characters. This is in line with the Ansem report from KH1 that stated the heartless only react to LIVING test subjects pic.twitter.com/DQPdlptO2WAugust 17, 2026
This theory started getting shared pretty widely among the fandom, and yes, that detail goes back to Ansem's Report 4, which appeared in the first Kingdom Hearts game. "The Heartless appear in groups, and are multiplying rapidly. I've provided them both living and nonliving samples," the report goes. "They've responded only to the living."
This detail actually manifests in a more meaningful way in the OG game, too. When Sora and the crew first arrive in Halloween Town, the Heartless are basically inert, and don't attack the largely undead Nightmare Before Christmas characters there. It's only after Skellington and Dr. Finkelstein build an artificial heart for the Heartless to pine after that they turn violent.
So it's entirely consistent with established lore that the Heatless appearing in the Land of the Dead are only interested in the one living being they see: Miguel. Honestly, bravo to Nomura and the rest of the crew. I doubt many would've noticed if that detail was swept under the rug, but the devs are clearly committed to making sure even the most obscure bits of Kingdom Hearts lore live on in the long-awaited sequel.
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