Brush of Death (life-steal)

You cover your hand with diamond dust which begins to create a blackened aura around your hand as you speak an incantation in your native dialect. You touch one enemy creature within range. Creature must make a Constitution Saving Throw (using your Spellcasting Ability as the DC), if the creature fails, it must take 10d8 necrotic damage which is then added to your hit points as temporary hit points. If the creature succeeds the saving throw, it takes half of the 10d8 damage that was rolled and the damage is not added to you as temporary hit points.

At higher levels, when you cast this spell using a spell slot of 7th level or higher, add an additional 1d8.