Also, I think Sora is simply the "chosen one" of the KH universe. MX said that the world has been almost swallowed up by many times, but each time it is saved by a boy weilding the keyblade etc. etc. Sorais probably the boy who can connect his hearts with others. That is his power. Ven says something about that being his power as well in the trailer. Maybe they both have this power, maybe Ven has it because he is connected to Sora.