i just saw the jump festa 2010 and this theory sorta jumped to my head
in the trailer MX talked about the keyblade wars legend and stuff he said he wants to know when will the light appear
so here is my theory:
MX thought that if too much darkness appears the light will finally come so he made Terra ( maybe vanitas too ) use his darkness for the wrong stuff and make his darkness stronger thats why we see him explode in anger and darkness in the trailer but the light did not appear so MX had to do something so he fused with Terra and Terra became xehanort
i dont support the terra is xehanort thing but this theory sounds possible
in the trailer MX talked about the keyblade wars legend and stuff he said he wants to know when will the light appear
so here is my theory:
MX thought that if too much darkness appears the light will finally come so he made Terra ( maybe vanitas too ) use his darkness for the wrong stuff and make his darkness stronger thats why we see him explode in anger and darkness in the trailer but the light did not appear so MX had to do something so he fused with Terra and Terra became xehanort
i dont support the terra is xehanort thing but this theory sounds possible