If you can get through all the levels of the Dark Realm you will recieve the Bishamon Ocarina from the chest. This Ocarina opens the door in the room with the magic fountain just inside the true dark realm. The door looks different from the rest of the wall. Oncxe your in the room, head towards the figure in the wall and you will be given the Bishamon Sword!!! This sword uses magic but doesn't use up any magic points.
Ok if you find 2 guys that hang down from above you and you try to talk and it says "its better to leave this person alone right now." beat the game and save then go back to him and he will take you to a place where there are Demons, defeat them then you will have to see what happens yourself because its different all the time.