(Hemomancy)
You draw out your own blood as well as the blood of corpses within 20 feet of you. You may choose to expend a number of hit points, and you may also gain the hit points needed from corpses within the radius. Each corpse that had a hit point maximum greater than or equal to 5 in life gives 5 hit points towards the casting of this spell, and then cannot be used to cast this spell again.
As a bonus action on your next turn, you release the blood. Each creature within 20 feet of you must make a Dexterity saving throw. On a failed save, they take 4d8 + the number of hit points spent as necrotic damage. On a success, they take half damage.