Who in the world even thought up the idea that Zelda could be Skyward Sword/Master Sword? Does the sword's "human" manifestation look anything like Zelda? How does that make sense? It's not any of the sages or other fan-favourite characters either. It's a new character. It's the spirit of the Master Sword. We'll learn more about it when the game comes out, but it's pretty obvious who the sword is not.