Hey y’all so I don’t know if these questions have already been answered somewhere else or if these are new but here I am. 

Spoiler

 

1. In kh 3 Sora is plainly told that he has three hearts in his. We know that  Ven and Roxas were two of them however what, was left unclear in my mind was whether or not Xion was the third. The reason I say this is because Org. 13 had Xion as a member and there was no evidence to support that a heart that belong to Xion left Sora’s body (also Xion being made up of his memories may make things difficult) my question being, did the third heart residing in Sora belong to Xion or someone else. 

2. When Sora and Riku saved aqua they, of course, welcomed her back to the realm of light. The realm of light is split into many worlds (this is a basic fact of the games so sorry if I sound a little dumb.) my question is is the dark world is its own world in the realm of darkness or is the dark world the entirety of the realm of darkness. In layman’s terms. Is the realm of darkness also split into worlds like the realm of light or is it its own world. 

3. This question has probably already been asked by many people but I just need to say it. Was Kairi actually at the Destiny Islands or was she just there “in spirit” like Sora was. 

 

 

Sorry if these are dumb questions but I’m really curious. 

To answer, or rather theorize as there are no "official" answers really:

Spoiler

 

1. The fact that the first heart was said to be with Sora most his life, and the second and third were said to be with him for "almost the same time" that strongly implies Roxas and Xion, and the fact that Xion was in his heart when he went into the World that Never Was during the Mark of Mastery exam in DDD, it essentially confirms that theory. When it comes to Xion in KH3, when you are fighting her, she starts to repeatedly attack Sora, and at the end of her attacks Sora says "It's all right, Xion!" which kinda triggered her memories to start to return. Xion had a different relation to Sora than Roxas or Ven, in that while her heart existed within him, they had a more ethereal connection throughout the series. Ven literally took shelter with his heart inside Sora's, and Roxas rejoined Sora to become whole again, so his heart also joined fully. Xion... kinda just had her connection and that was it, she never met Sora, her memories were always connected with him, but her heart didn't go to seek shelter within his the same way Ven's did, nor the same way that Roxas' did by rejoining him.

2. As far as we know, the Dark World and Realm of Darkness are.. essentially interchangeable terms. There hasn't really been a real distinction between them other than who referred to it and when. Realm of Darkness tended to be used more early on and made way to the Dark World term (likely because it, as a whole, is the opposite of the World of Light (Realm of Light)). While we see different areas and different zones, 0.2 shows this all really well, we don't really see it divided into Worlds like the Light counterpart.

3. This is likely the most contested and hard to answer question. Personally I feel that neither of them are there. Neither of them are on the tree until they suddenly are. The only reason that truly lends credence to the counter, Kairi actually being there, is that she starts crying. If Kairi made it back and Sora didn't, it would be understandable why she was crying. Now one answer as to why they weren't on the tree could be they walked over quickly while the area wasn't visible, but I don't feel they would have done that. However, an answer I do feel is possible: Sora rescued Kairi's heart, she reappeared in the Realm of Light and due to Destiny Islands having such a strong connecting to the Realms of Darkness and Light, it's possible that she returned to the islands and literally reappeared on the tree, which would explain why everyone suddenly stops and looks over there. It would also explain why, if Sora wasn't able to fully make it back at that time, that he would still have a temporary form. But personally I feel even that is a stretch and likely neither of them have fully made it back and it was just showing the pain in both their hearts for the moment that they were struggling to find each other and return together.

 

 

Those are my interpretations of things so far. Obviously, as I said, we don't really have anything official that I was able to find, but I hope those help or possibly provide other angles from which possibilities might exist for your own theories.