So, first: I'm in the last room in the Temple of Time, the one with the waterfalls, but where do I go now? Nothing seems to be behind them and the doors are all locked...

Second question: how do I beat Odin? Someone in a village told me he locked himself under the sea because he "was afraid of his own power", but I can't get what it is. He uses no elemental attacks. Do I have to use Bolt3 like in FF IV?
Thank you !!