Okay, this isn't a theory, just an idea for the ending of BbS.
Okay, so, on the case of Xehanort, maybe at the end, we find out that Vanitas is actually a replica of Terra, but an imperfect replica, and this replica is Xehanort, only his name at this point is Vanitas. This is why he doesn't look like Terra, with the hair and eye color. Terra and Vanitas have a battle or something, and maybe something involving a combination of MX and Vanitas or something, and there is a HUGE explosion, and Vanitas is shot around the universe, to radiant garden. He is still in his armor. Dilan and Aeleus bring Vanitas to AtW, and take off his mask to show Vanitas, or Xehanort.
Now, on Ven. This one isn't as long, but still expanatory, if that's a word. I don't know who, but someone takes a dead, sleeping, dormant Ven, whatever you want to call it, to Castle Oblvion. If I am correct, the Chamber of Waking is in castle Oblivion, and if I am also correct, Ven is in the Chamber of Waking, seeing as Aqua's armor is in the Chamber of Repose.
Okay, so, on the case of Xehanort, maybe at the end, we find out that Vanitas is actually a replica of Terra, but an imperfect replica, and this replica is Xehanort, only his name at this point is Vanitas. This is why he doesn't look like Terra, with the hair and eye color. Terra and Vanitas have a battle or something, and maybe something involving a combination of MX and Vanitas or something, and there is a HUGE explosion, and Vanitas is shot around the universe, to radiant garden. He is still in his armor. Dilan and Aeleus bring Vanitas to AtW, and take off his mask to show Vanitas, or Xehanort.
Now, on Ven. This one isn't as long, but still expanatory, if that's a word. I don't know who, but someone takes a dead, sleeping, dormant Ven, whatever you want to call it, to Castle Oblvion. If I am correct, the Chamber of Waking is in castle Oblivion, and if I am also correct, Ven is in the Chamber of Waking, seeing as Aqua's armor is in the Chamber of Repose.