Elemental Attunement

You attune yourself to one element, which you choose upon acquiring this feat. This damage type can be Acid, Cold, Fire, Lightning, or Thunder. Upon hitting with a weapon attack, you can choose to deal this damage instead of the normal weapon's damage type. (For example, 1d12 Slashing damage could become 1d12 Cold damage). In the case of a sword that already does elemental damage, such as a Flame Tongue, the Flame damage stays the same but you can replace the Physical damage with your attuned element. You can only choose this feat once, and you can't change your attuned element.