Quote Originally Posted by PuPu View Post
Nobodies correspond with the person's body (I think)
Nobodies are what are left behind when the Heart leaves. They are both Body and Soul. They sure are no Kel'Thuzad.

Quote Originally Posted by Jessweeee♪ View Post
I've always wondered what the difference between someone's heart and soul was supposed to be >.>
In over simplified terms, the Heart defines your existence. It gives shape to all of the emotions and actions that a person can go through. Let's say I can walk, talk, procreate, and inject my Acids into other organisms, turn them into factories, and watch them explode. But those could all be one big giant Python code as follows:

Code:
import virus;


Sure as hell isn't a person, though. Nobodies always complain about not existing, but it is certain that they are alive. They walk, talk, breathe, and create large amounts of fireworks. But they don't act irrationally. Just pissed and like bratty teenagers.

The Soul defines whether or not you are alive. It is clear that Unbirths existed first, because they are being fought in the prequels (no skullskullskullskull, Sherlock). The first game states that Heartless didn't exist until Ansem's (both the real and the fake) experiments. Nobodies therefore, must not have existed until after the first Heartless formed, and even then, Nobodies are formed from the desires of a person who is willing in the first place. Even if we went by the original Ansem reports, Xemnas doesn't appear until the end of the last one, which is only slightly before the beginning of KHI, and after he found out how to manufacture false Heartless.