Multiattack. The ashenwight makes two Necrotic Shard attacks.
Necrotic Shard. Melee or Ranged Weapon Attack: +7 to hit, reach 5 ft. or range 60 ft., one target. Hit:7 (1d6 + 4) necrotic damage. If the target is a creature, it has disadvantage on the next attack roll it makes before the end of its next turn.
When a Humanoid consumed by cruelty and rage dies in an area corrupted by the Far Realm, the creature sometimes rises as an ashenwight. The skin of these Undead horrors is desiccated, and their eyes often glow with otherworldly power.