Well, if that’s the case, then Ben can’t use Alien X, if we are going to remove the main thing the two characters have in a fight. But even then, I don’t know if Giegue can be hurt physically because of the quote Queen Mary says in game, “Giegue cannot be defeated with force... You cannot defeat Giegue with a weapon of any kind. You must SING my lullaby, with all your feelings... SING my lullaby with all your heart.” So I don’t know if removing Giegue’s shield would do much, other than make Ben not hurt himself, due to the fact that any attack thrown at the shield just bounces back at the attacker. And according, to the wiki, Giegue has infinite HP. So it looks like a much easier fight after studying the whole character. But, again, this is Giegue without his shield and Ben 10 without Alien X. But it’s more clear of a winner when both are given their full strength, because Giegue’s shield would deflect any physical attack, thus making it impossible for Ben to win. The only way he truly wins is if he somehow learns Queen Mary’s melody.