Life Caster

You have learned to channel your own life force to power your spells.

Ability Score Increase: Increase your Intelligence, Wisdom, or Charisma score by 1, to a maximum of 20.

Vitality Casting: You can cast spells you have prepared by expending a number of Hit Dice equal to the spell's level. For each Hit Die expended in this way, you take necrotic damage equal the roll of the Hit Die plus your Constitution modifier, this damage cannot be reduced in any way.

You can only cast spells at 6th, 7th, 8th, and 9th levels using this feature once each, and you regain the ability to do so after completing a long rest.