Kingdom Hearts 4 is on the way, and speculation about what worlds could make it into the game is rampant among the fanbase. Originally a crossover between Final Fantasy and Disney, the KH franchise has visited no shortage of iconic licensed worlds in animation over the years. The series has established its world selection to be composed of both modern and classic film IPs since the first game, but Kingdom Hearts 4 has the opportunity to represent the widest spectrum between the two yet while helping Disney to maintain aging parts of its brand, like Steamboat Willie.