Introducing Star Wars and Marvel into Kingdom Hearts is difficult for contractual reasons

Whether Kingdom Hearts has something from Marvel or Star Wars does not depend entirely on Disney no matter how much they collaborate with Square Enix. They already had trouble getting Mickey into the first game.

Since Disney acquired Star Wars and Marvel, their inclusion in Kingdom Hearts has been in demand. Since the game is a collaboration between Disney and Square Enix, it is thought that inserting the characters and space or comic worlds would be easy. But Tetsuya Nomura says that doing so would be very difficult.

Contracts are big problems for Kingdom Hearts

Tetsuya Nomura commented in an interview for the Ultimania book that getting Star Wars or Marvel into Kingdom Hearts would be difficult. To do this, it would be necessary to contact Marvel and LucasFilm separately and reach an agreement with each.

Tetsuya Nomura gave as an example the rights to use Mickey Mouse's image for the first Kingdom Hearts. Close to the release of the first game in Japan, Disney's Magical Mirror Starring Mickey Mouse was released by Capcom for the Gamecube. Being a game starring Mickey by transfer of rights, Square Enix had to ask permission for it to appear in Kingdom Hearts. Finally they could under the condition that it was only a scene in which he is seen from afar and is only a silhouette "waving his wand or something".

Without Nomura mentioning it, another rights issue was with the rights holders to the Tarzan books. They could introduce the world in the first Kingdom Hearts but in Chain of Memories that recalls the worlds of the first game they could not. Basically, the series is much more comfortable using worlds belonging to Disney movies and characters.

Some will mention the case of the Kingdom Hearts III world of Big Hero 6, which is a Marvel comic. But the world is based on the Disney adaptation and not on the original comic, so there are no rights issues.

Source: Gameinformer