Death Knell

You invoke the final breath of the dying, sealing their fate and reaping their soul for power. Choose a creature within range that has less than half of its hit points remaining. Make a melee attack upon a hit, the target must make a Constitution saving throw. On a failure, their hit points are instantly reduced to 0, and you gain temporary hit points equal to their remaining HP before the spell took effect.

If the target succeeds on the saving throw, they still take 6d8 necrotic damage.

At Higher Levels: When cast using a spell slot of 5th level or higher, the necrotic damage increases by 1d8 per slot level above 4th.