This is my way to beat the giant rat in Neptu's Temple. First, read the glitch duplicate items. Then duplicate the strongest magic and weapons/magic(ex.Antarctic wind).Okay, so you will notice he has the other eye for the sea monster. Before you fight, make sure all of your party members have full health. Then use a spell or item to grow you big again. Make sure you have at least 2 mages, a warrior, and freelancer. Give the freelancer the strongest weapons(the freelancer should be the mian character) could if you read the sentence inside the parentesis it should be the highest job level in your party. Then give the mages the strongest magic. The warrior the second strongest(second strongest in your party for the battle). Then save right before you battle him(right when you see him). To read the rest, read beating the giant rat 2.