Corrupting Presence

A corrosive aura emanates from you, depleting the enemies in your presence. As an action, a hazy unnatural shadow spreads in a 20-foot-radius sphere around you,. The shadow moves with you and spreads around corners; the effecting lasting for one minute, or until the effect ends or concentration is broken. The area within the sphere counts as dim light.

When you cast this spell effect, you can designate the number of creatures you can see to be unaffected by it. An affected creature's speed is halved in the area and when the creature enters the area for the first time on a turn, or starts its turn there, it must make a Constitution saving throw. On a failed save, the creature takes 3d10 necrotic damage and suffers one level of exhaustion. Any level of exhaustion caused by this ceases when the spell effect ends.  (Cost: 3 Siphons)