OK the kingdom key represents light. It is debatable what riku's way to the dawn represents, whether its twilight or dawn. It is never stated that mickeys keyblade represents dark. Now what happened to the dark keyblade? And before you go off saying it was formed by the seven princesses of heart. Guess what it wasnt. Fake Ansem wielded it when he was possessing Riku. My guess is the dark keyblade represents darkness. Just a simple thought that came to mind. But whats your theory?