Ventus-X

I think its revolves around sora dreaming when he was asleep for the year because it couldnt be before KH, not before COM, the year he was asleep after COM is the only opening because he gets a new outfit for KH2. I think it is about him gaining his memories during the year after COM. The only reason is because he had no keyblade before KH, after KH thre was COM after there adventure, after COM he went to sleep restoring his memories, after he got his memories and was awake he got a new outfit. To me the story of Kingdom Hearts 3D is during the year of his absence.

The first person to wear the orginization cloak was MX seen from opening of BBS so it is a possibility that it is someone MX was close too. That is what I am thinking until release of the game.

Could be a whole new type of enemy like Vantias.

I think it could have been a apprentice of Master Xehanort before Ventus.