As an action, you siphon life force from a creature that you can touch or see within 10 meters to heal your wounds. The creature must make a Fortitude saving throw. If the creature is a construct or an undead, the spell has no effect on it.
On a failure, it takes 3d8 necrotic damage.
On a critical failure, it takes twice as much damage.
On a success, it takes half as much damage.
On a critical success, it takes no damage.
You regain health equal to half the amount of necrotic damage dealt.
You can increase the damage by 3d8 for each additional mana expended.