Series creator and director Tetsuya Nomura has confirmed that Sora's realistic look in Kingdom Hearts IV comes down to a lore reason.

Kingdom Hearts IV's trailer was filled with many surprises, but there was perhaps no greater surprise than Sora's new look. More realistic and lacking the Disney clown shoes, the new look screamed real-world. It turns out that that was intentional. It is because Sora is in the world of Quadratum that he looks this way, and that he might not if he can return to his world.

In an interview with Famitsu (translated by VGC), creator and director Tetsuya Nomura provided more details about the nature of Quadratum. As we learned from the trailer, Quadratum is a sort of 'afterworld' for Sora. Real-world locations like Shibuya and Minami-Aoyama exist in this world, or, as Nomura puts it, alternate world.

“From each of our perspectives, our perceptions change. In [mobile game] Kingdom Hearts Union χ, the Master of Masters said something along those lines. From Sora’s perspective, Quadratum is an underworld, a fictional world that is different from reality. But from the point of view of the inhabitants on the Quadratum side, the world of Quadratum is reality, and the world where Sora and the others were is the other side, the fictional world. I think the theme of this project will be the contrast between those who are in such different positions.”

Juxtaposing the realistic look is the scene with Donald and Goofy at the end of the trailer. Though the visual fidelity is leagues better than what was seen in Kingdom Hearts III, both they and the landscape still have that Disney look to them. Should Sora find his way back, he would revert to his more traditional look. There is strong precedent in Kingdom Hearts for Sora to change looks based on location. For example, Sora turns into a Merman when visiting Atlantica, a lion in Pride Lands, and a monster, in Monstropolis.

“Donald and Goofy are looking for clues about Sora in the original world. All the real worlds before the title display [in the trailer] are all Quadratum segments and Sora will look realistic, but if he can return to the original world, he will look like Donald and Goofy with shaders like Donald and Goofy.”

Kingdom Hearts IV is the first chapter in the new 'Lost Master Arc.' The game will run on Unreal Engine 5. Rumored worlds based on the trailer include Endor (Star Wars) and Olympus (Hercules). No word yet on a release date or platforms.