As an action, make a weapon attack.

On a hit, add 3d4 + your spellcasting ability necrotic damage to the attack’s damage roll.

On a critical hit, it takes twice as much damage

On a miss by 4 or less, add half as much damage.

You siphon the creature’s life force to heal your wounds as you regain health equal to half the amount of necrotic damage dealt.

Augment

You can increase the damage by 5d4 for each additional mana expended.