Blood Magic

Prerequisite(s): 6th level, Ability to cast at least three spells

As in Unearthed Arcana: Heroes of Krynn Revisited Adept of the Black Robes with the following change:

Life Channel. You can channel your lifeforce into the power of your magic. When a creature you can see within 60 feet of you makes a saving throw against a spell that deals damage that you cast, you can add an additional number of d6s to the damage. You have a number of d6s equal to your proficiency bonus that can be spent, and you can expend Hit Dice to add additional d6s equal to the number of Hit Dice expended. The total number of d6s that can be added is equal to the level of the spell. Roll the expended d6s and add them together. The damage that the creature takes increases by an amount equal to that total. If any of the dice have a result of 1 or 2, the number of Hit Dice or uses are refunded equal to the number of dice with a result of 1 or 2. Your free uses are regained at the end of a Long Rest.