Well we can't prove or disprove anything. The keyblade was meant to be handled by Riku. His heart has allowed the darkness within him, and then he was unable to use a pure keyblade. If Terra is indeed Xemnas, then he's 150% EVIL and thus, can't use keyblades on his own, unless he was able to create a dark one, which he didn't. But whoever Xemnas is, the keyblade point is irrevelant. BBS will show us his past. Since Xehanort shows up at the end, whoever he is, he's one of the main characters, so he used a keyblade before (weither he is Master Xehanort, Vanitas, Ven, Terra...). And don't forget Sora was still alive, thus making Roxas special.
Is Terra Zehanoto :
Cons :
- Why doesn't Mickey remember Terra, since he recognized immediately Xemnas, while this one differs from Xehanort ?
Pros :
- Hairstyle
- Terra turning to the darkside at the end of the game (he wouldn't just turn and then get killed, it would be lame since they're hinting that scene since BBS video and during the whole game, by allying dark beings)
- Xemnas referring to Aqua as a friend
- Terra is the only one in the game to have an appropriate height, matching Xemnas'
- He has a lot of connexions to Riku(he even chosed him to be the keyblade's wielder). Xehanort's hearless tells Riku "they are similar".
- It can't be Ven Aqua nor Vanitas (we've seen the shape of his eyes, colour of skin, and he's too small)
- His hatred toward Master Xehanort animated the lingering sentiment, a powerful emotion, maybe that's why it's the only thing he remembered.
- It can't really be "Master Xehanort", there would like, no cliffhanger at all !
Theory :
