Rimecaster

Prerequisite: A race or background from a cold climate and the ability to cast at least one spell

You are from an area with a cold climate and have learned to adapt your magic to reflect your heritage. You gain the following benefits:

• When you cast a spell that deals damage, you can use a reaction to change the type of damage the spell deals to cold damage.
• When you cast a spell that deals cold damage, you gain resistance to cold damage until the start of your next turn. If you already have resistance to cold damage, you are immune to cold damage until the start of your next turn instead.