The only other Unknown to make an appearence in the American version "Another side, Another story". The Unknown wears a blindfodl over his eyes rather than wearing his hood up. This is the Unknown the the Duel Wielder passes the Oblivion to. There is strong evidence that this Unknown is none other than Riku.
First clue: If you look at Riku then the Blindfolded Unknown, you'll see that their hair type and color are almost exacally the same.
Second clue: Because of Tetsuya Nomura's offical statement that one of the five Unknowns in Deep Dive would be Riku. One could assume that this Unknown is Riku because of the physical resemblace and the fact that he was the only other one in the game that could use a Keyblade.
