Magic Reserves

You are able to harness the flow of energies and elements around you, harnessing them for your next attack. When hit with an attack that would do damage other than piercing, slashing, or bludgeoning, you can hold onto part of the damage and then release it as an action on your next turn by adding 1d6 damage of that type to your attack.

Possible types of triggering damage: Acid, Cold, Fire, Force, Lightning, Necrotic, Poison, Psychic, Radiant, Thunder.