Deep Magic Volume 2 (p.145)
Blood Shards
5-level Necromancy
Casting Time: 1 bonus action
Range/Area: Self
Components: Verbal, Somatic, Material
Materials: a drop of your blood
Duration: 1 minute
You draw vitality from yourself, corrupt it, and fill your strikes with the corrupted essence. Until this spell ends, each time you hit a creature with a melee weapon attack, roll your choice of 1d4, 1d6, 1d8, or 1d10. You lose a number of hit points equal to the number rolled, and the target takes necrotic damage equal to three times that amount. The spell ends early if you end a turn below half your hit point maximum.
Available for: Bard, Cleric, Sorcerer, Warlock