https://www.gamespot.com/articles/comic-con-2018-kingdom-hearts-celebrates-90-years-/1100-6460618/

What would a Final Fantasy and Disney crossover be without the main mouse himself? In a new Kingdom Hearts III trailer revealed at SDCC 2018, we got to see all the wonderful contributions Mickey Mouse has made to the story in celebration of his 90th anniversary.

For Kingdom Hearts, Mickey plays a key role as king and travels to other worlds to defeat the darkness. But his royalty and leadership aren't exactly where his actual story begins in the series.