If Kingdom Hearts 4 doesn't plan to pull Clive from Final Fantasy 16 for a crossover, the series still has a strong and relevant option at its disposal. Both Kingdom Hearts and Final Fantasy have been intertwined in at least some way since the beginning of the series. It would be no surprise at all to see Kingdom Hearts 4 feature another Final Fantasy character crossing over into the world. The question is whether it will be the latest protagonist Clive or someone else. After all, there are still valid options even if Clive gets passed over.