okay, I'm not exactly sure how to explain this one, this isn't truly a big huge deal but has been haunting the back of my mind forever. I just have to get it out. I think at one point of the BBS storyline, One of the three knights (call me crazy but I think Aqua) will cross paths with young Kairi during a unbirth/first heartless invasion. Then they will try to take her away for some unknown reason and that is how she ends up on Destiny Islands. I know this theory has really no point but I had to get it out.