Do level 1 dungeon in the Dark world and then go to the Village and into the level 4 dungeon in the dark world. Then go into it halfway to get the titan's mitt. Go by the Library south of the vilage to find a little frog-like thing and use your magic mirror and take him back to the blacksmith and give them your master sword and they will temper it to give you the tempered sword. It should make it real easy for level 2-5 dungeons in the dark world.