Eh, I guess I'll just throw it in here because I came up with it last night and frankly, I like this more than just a walking heart.
Here's the difference between the original Xehanort and the Young Master Xehanort:
Xehanort:
- deep voice
- definitely seems to be older than say Sora and Riku
- stays on the island until he finds a way to get off, and gets a Keyblade, then adventures until he becomes the old Master Xehanort
Young Master Xehanort:
- takes upon a more high pitch voice
- it looks as if he grew younger, looks like he's around Sora or Riku's age in KH2.
- has time traveled fowards in time to collect Xehanorts before their death, in the process gets a Keyblade
Because of their differences, I'm doubting that the original Xehanort time travels and manages to take this VERY DIFFERENT form because he is a walking heart. And idk if you realize it, but the original, before time traveling, has not obtained a Keyblade yet. So when we see YMX throw out a Keyblade in front of Riku and Mickey, it's a little suspicious.
There are two ways he could of gotten a Keyblade. One would be the Rite of Succession, and I'm not going to believe that one of the Xehanorts he brought back was, "KTHNX HERES THE ABILITY TO USE ONE, AND YOUR VERY OWN KEYBLADE, YAAAAAY!". Or the second option would be of course, if a Keyblade Wielder's heart resides in a body of someone. Now Sora can use the Keyblade, because he had a strong heart. But after seeing the Xehanorts taunt Sora that he isn't a true Keyblade Wielder through out the entire game, I'm starting to lean towards that thanks to Ventus, he is able to wield the Keyblade. How it's seen, it can go both ways.
For someone like YMX, who time traveled in the future, lost his form, and when he finally did get a new form, it was a more younger version, and he was able to wield a Keyblade, since I guess you can say that originally he was going to obtain one, but the time traveling missed his chance to do so, I don't think a walking heart could of managed all this. There's just little reason to call it out on that.
So firetruck it, I'll just say it.
His heart is harboring inside someone else's body, as a vessel. Out of pure speculation, I want to say Vanitas. Vanitas has not appeared in the entire game, except for the one instance where YMX approached Sora in the Hunchback world, and Vanitas appeared, but as an illusion.
Here's what really leading me to think it's Vanitas. Now assuming YMX saved Vanitas within his time traveling, or any possible reason Vanitas could of came back, he would use Vanitas as a vessel for Xehanort or Xehanortified him. Vanitas....isn't exactly a slave to MX in BBS, if you remember correctly. Vanitas, instead, would disobey his orders, to the point of ending his entire plan to forge the X-Blade, simply by ending Ven's life. Basically, Vanitas doesn't care about MX. His focus was on Ven and pretty much Ven only. Sure, the occasional Aqua, but that's for if Ven could not be a proper being to merge with to forge the X-Blade. And that's pretty much it, just his focus on Ven, because he is "dark side" after all. So when I think about it, you can imagine how Vanitas could of reacted to Xehanort's plan to use as much people as vessels for him as possible. Vanitas wouldn't care for his plans, and at that point, would either go back to the X-Blade plans or go after Ven himself. That's why if he is, or going to be, a vessel, there is that feeling that Vanitas would resist to the whole thing, resist to Xehanortification. And that's what I think happened with Vanitas. He resisted, and eventually he was forced. By that time, YMX needed a form, so he would put his heart into Vanitas, and boom, there he is, the YMX we see in 3D.
How do you determine it can be him? Well simple really. The heart in body conspirarcy is that when a heart enters a body with someone's heart, some actions may occur. If the heart does not do anything or is dormant, then the body will stay the same. But if the heart tries to take over, then the body starts to gain physical traits, that of the heart that's taking over. If YMX's heart tried to take over Vanitas' body for absolute control, it's going to start looking like him. And thus it does. And when he does finally take that form we see now, his voice, his body, and overall, is more newer and younger. If that's true, then it looks like either Vanitas's heart is weak at the time, or YMX/MX had made it weak.
Going back to that illusion, it would appear that Vanitas doesn't look like he's a part of him, but does say exactly what YMX had said, at the same time. Explaining is rather tough. It's like if illusion was supposed to signal that this is his body, but himself in control. Like if Vanitas was saying it to him, but in reality, he wasn't, but YMX was. The illusion there seems kinda unlikely to just throw Sora off (especially since you can't really throw someone off when they don't understand anything at all). But of course, anything is possible.
Now the for the Keyblade part. Vanitas can wield his own Keyblade, which is known as the Void Gear. And like I discussed above, YMX missed his chance to wield his actual one because of time traveling. So in order to even be able to get a Keyblade, one of the few ways he has is to use Vanitas' heart to give the power to wield one. As for obtaining one, that I wouldn't be able to exactly figure out, but he could of gotten a Keyblade along the way, it's not entirely impossible. It's like Mickey grabbing the Kingdom Key D, which was a Keyblade of the Realm of Darkness, a Keyblade literally being there. And it become his official one, besides his Star Seeker (and I think that is Yen Sid's anyway, only logical). To show that YMX could be using Vanitas for a Keyblade is if you look closely at his Keyblade, which is hard to see, but I have managed to pause one of the videos in time to get a look. It'll be one of the attached. Assuming you saw the attached photo, you'll see those are gears on his Keyblade, which Vanitas' Void Gear consisted of LOTS of gears. This could be a sign for his time travel of course, but since Vanitas is the only person that has gears on his Keyblade, you can say there could be a slight connection to it. Not quite, but close enough.
But what happens to Vanitas after this? Well YMX does mention that he would be returning to his original era. I'll assume that when he does return, he'll return to his past like how it should of happen, nothing rewritten like it should have. He would return to his original self, and Vanitas would stay back. And at that point, MX will probably just use Vanitas as a vessel once more, probably being very weak from being used and Riku beating the shit out of his body, and he'll probably just be Xehanortified sadly.
Or I could be extremely off and I am just out of my blooming mind. But as of now, I'll stick with this then a walking heart lol.
EDIT*
Nevermind, I'll just post the image here, to be easier.
Edited by Tom, 03 April 2012 - 06:45 PM.
Daniel Chiuchiarelli