i think that...Mickey, Donald and Goofy would come to destiny Islands to warn Sora,Riku and Kairi of a new enenmy that got created from the death of Orginization 13, and the the strongest heartless Sora has fought... Sora and Riku would be attacked by the new enemy, the Heartless Nobody, Riku would try to become dark again after mickey was turned into a heartless and nobody and absorbed by the H.N... he would fail and then would become a heartless and nobody himself, and also absorbed by H.N... Sora would then fuse with Kairi,Donald, and Goofy to create, Prince of All Hearts, Keywielder... this would be a new form, he would have longer,yellow hair, red clothes, and 2 keyblades, Prince and All Hearts, which you take, Prince of Alll Hearts life when he got very weak from fighting the hopless battle with Heartless Nobody, and the hearts that H.N would be realesed, but Mickey's,Sora's,Riku's,Donald's,Goffy's, and Kairi's hearts would be taken away to keep Heartless Nobody locked away inside of Kingdom Hearts.