Mask Wight

Necrotic Weapons. The mask wight's weapon attacks are magical. When the mask wight hits with any weapon, the weapon deals an extra 3d8 necrotic damage (included in the attack).

Single-Minded Purpose. The mask wight has advantage on attack rolls against fiends and creatures wielding fiendish power, such as tieflings or some sorcerers and warlocks.

Undead Nature. The mask wight doesn't require air, food, drink, or sleep.

Multiattack. The mask wight makes two Khopesh of Oblivion attacks and one Spiked Gauntlet attack. If both Khopesh of Oblivion attacks hit one creature, the target must succeed on a DC 17 Wisdom saving throw or forget cherished memories of one object or location until it interacts with that object or location again. The object or location can't be an object on the target or a location within its sight when it fails this saving throw.

Khopesh of Oblivion. Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: 15 (2d8 + 6) slashing damage plus 13 (3d8) necrotic damage.

Spiked Gauntlet. Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: 13 (2d6 + 6) bludgeoning damage plus 13 (3d8) necrotic damage. If the target is a Large or smaller creature, it must succeed on a DC 17 Strength saving throw or be knocked prone.

Wail of the Forgotten (Recharge 6). The mask wight emits an ear-piercing wail. Each creature within 30 feet of the mask wight must make a DC 17 Charisma saving throw. On a failure, a creature takes 35 (10d6) thunder damage and 27 (6d8) psychic damage and is deafened for 1 hour. On a success, a creature takes half the damage and isn't deafened. A creature killed by this wail is erased from the memories of every creature in the planes that ever saw or interacted with it, all written or pictorial references to the target fade away, and its body is obliterated. Only divine beings and creatures that saw the creature die are unaffected by this memory erasure. The slain creature can be restored to life only by means of a true resurrection or a wish spell.