Enchantress

The Enchantress would be a rare villager found randomly in any level, set up with a little shop in a door. The function of the villager is to move enchantments from one slot to another. This could be done once per weapon/armor and would allow for four enchantment choices in one slot if the player chose to do so. This would mean that enchantments wouldn't be added or removed, it would just allow new combinations for the enchantments already on the weapon. Currency could be emeralds, gold, or a combo of both.