It's been a long wait for Kingdom Hearts fans. Part of that missing puzzle was supposed to come from Kingdom Hearts: Missing-Link, the mobile game that was expected to help connect the events of Kingdom Hearts III to Kingdom Hearts IV. Some believe it's Quadratum, the realistic world teased for Kingdom Hearts IV. Others think it could instead be Scala ad Caelum, one of the major locations introduced in Kingdom Hearts III. Kingdom Hearts has always blended fantasy, Disney magic, and anime-inspired character designs, even when introducing advanced technology.