You draw blood from a target, unleashing it as a violent storm of ichor. Choose one creature within range, which must make a Constitution saving throw. A creature takes 4d6 necrotic damage on a failed save, or half as much on a successful one, and its hit point maximum is reduced by an amount equal to the damage taken.   In either case, you draw some of the target's blood from its body, unleashing it as a storm of blood which extends outward from the target in a 10-foot radius for the duration. Each creature that starts their turn within the ring or moves inside of it for the first time on a turn, including the target creature, must make a Constitution saving throw. A creature takes 4d6 necrotic damage on a failed save, or half as much on a successful one, and its hit point maximum is reduced by an amount equal to the damage taken.