Heliana's Guide to Monster Hunting, pg. 508
3rd ring Arcane, Necromancy
You drain the life force of those around you, turning their limbs heavy and their bones cold. Each creature of your choice within 20 feet of you must make a Constitution saving throw. A target takes 2d8 necrotic damage on a failure, or half as much damage on a success. The caster regains hit points equal to half the total amount of necrotic damage dealt to Small or larger creatures.