concentration, 1 minute/mana
As an action, a black beam of enervating energy springs from your finger toward a creature within 10 meters. The creature must make a Fortitude saving throw.
On a failure, it takes 3d10 necrotic damage and deals only half damage with weapon attacks for the duration.
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.
The creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
Augment
You can increase the damage by 4d10 for each additional mana expended.