Elemental Mastery

Prerequisites: The Elemental Adept feat over the chosen element.

When you gain this feat, choose one of the following damage types: acid, cold, fire, lightning, or thunder. You gain the following benefits:

• Spells you cast that deal damage of the chosen type cause half damage to creatures with immunity to that damage type, instead of zero. In addition, when you roll damage for a spell you cast that deals damage of that type, you can treat any 1 or 2 on a damage die as a 3.
•  You can select this feat multiple times. Each time you do so, you must choose a different damage type.