I have a theory about Xion appearing in the future game. It start like this do you remember a scene when Kairi restore Heartless Sora to his original self. Which makes me thinks Kairi use some of her body and soul to Sora. Why do you think Sora can still have a body and move? If Sora becomes a Heartless again and Roxas will be reborn with Kairi's body and soul and somehow use its parts to revive Xion. Xion
I have a theory about Xion appearing in the future game. It start like this do you remember a scene when Kairi restore Heartless Sora to his original self. Which makes me thinks Kairi use some of her body and soul to Sora. Why do you think Sora can still have a body and move? If Sora becomes a Heartless again and Roxas will be reborn with Kairi's body and soul and somehow use its parts to revive Xion. Xion