Aura of Impurity

Enervating energy radiates from you in an aura with a 30-foot radius. Until the spell ends, the aura moves with you, centered on you. Each creature of your choice that enters the aura for the first time on its turn or starts its turn there must succeed on a Charisma saving throw or become drained until the end of its next turn. While drained, a creature must roll a d4 and subtract the number rolled from each ability check, attack roll, or saving throw it makes, and any hit points a creature regains are reduced by half.