I dunno. I mean, I think it's just the common history that the majority of them went through, but there're probably little differences all over the place. And then there'll be people who have nothing in common except the names and personalities and relationships, like the Sora from my world.

[I hope you're not going to have some kind of freakout because we're talking about Sora. >_> I'm not sure I know how to deal with that.]