Logic is flawed.
Unbirths can destroy those sheilds just as well as heartless can.
you don't know that.
yeah cus in KH1 & KH2 heartless were the one's blocking off the worlds.
who said unbirths can't be doing the same as the heartless did.
what?! heartless. blocking. worlds? do you understand what you are saying? no one was blocking anything! heartless got to worlds through dark portals, thus, shattering the barrier somehow, thus, opening a gate for the ship. in kh2, sora opened his own path. your sentence makes no sense.