Elemental Expertise

The ability to cast at least one spell

When you gain this feat, choose a single damage type from the following list: acid, cold, fire, lightning, or thunder.  

• Spells you cast ignore resistance to damage of the chosen type. In addition, when you roll damage for a spell you cast that deals damage of that type, you can treat any 1 on a damage die as a die re-roll.
• Each time this feat is selected, you must choose a different damage type.