Hmmm...I doubt that is Roxas and I don't believe that blonde-haired soldier is dead either and yes I may have proof. After viewing the Secret Video several times I noticed when the female soldier holds in the frozen soldier in her arms, when the camera zooms on his face..if you look closely at his eyes at the last second before the next frame, they look like they move towards the female Edit: My bad if someone already found that out, cause I just realized it after 183 times of viewing the vid.
