From the beginning, go up to the village and defeat the enemies there. After talking with your master, go left to the castle and talk to the king. He will give you a key to open the water temple. After looting the castle for goods, go right, past the town and find the water temple Defeat all of the guards there, picking up as many weapons and food items as possible, then proceed to the boss. If you picked up other weapons like swords, use them now. Attack the claw first then the mouth of the monster. Defeat the boss and proceed to the next room to get the water spirit and achievement.