Myrinthus

Multiattack. Myrinthus makes three attacks: two Grasping Hand attacks and one Masked Strike.

Grasping Hand. Melee Weapon Attack: +11 to hit, reach 15 ft., one target. Hit: 21 (2d10+7) bludgeoning damage, and the target is grappled (escape DC 22) if it is a creature Medium or smaller. Until this grapple ends, the target is restrained and Myrinthus can’t use that hand on another target.

Masked Strike. Melee Weapon Attack: +11 to hit, reach 10 ft., one target. Hit: 28 (4d8+7) psychic damage. If the target is concentrating, it must succeed on a DC 22 Constitution saving throw or its concentration is broken.

Veil of Many Faces (Recharge 5–6). Myrinthus exhales a shimmering cloud in a 60-foot cone. Each creature in that area must succeed on a DC 22 Wisdom saving throw or be affected by an illusion that alters its appearance and identity for 1 minute. While affected, a creature's memories of allies and enemies are scrambled: it treats former allies as hostile and former enemies as friendly for purposes of attacks, spells that target creatures by name, and social checks. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. Creatures that succeed are immune to this Veil for 24 hours.

Befuddling Riddle (3/day). Myrinthus speaks a paradoxical question to a creature it can see within 120 feet. The target must make a DC 22 Intelligence saving throw. On a failed save, the target is stunned for 1 minute. At the end of each of its turns, the stunned target may make another Intelligence saving throw, ending the effect on a success. A creature that succeeds is immune to Befuddling Riddle for 24 hours.

Divine Bargain (Recharge 6). Myrinthus offers a contract to up to three creatures it can see within 60 feet. A creature that accepts the bargain gains a sudden boon: choose one benefit — advantage on one attack roll, +20 temporary hit points, or teleport up to 120 feet — used within 1 minute. When the boon is granted, Myrinthus immediately selects a hidden, binding clause (DM’s choice) that triggers within 24 hours unless the recipient performs an act determined by Myrinthus. Creatures may refuse the bargain; a creature that accepts is charmed by Myrinthus until the bargain’s clause is fulfilled or broken.

Legendary Resistance (3/Day). If Myrinthus fails a saving throw, it can choose to succeed instead.

Slip Away. When a creature misses Myrinthus with an attack, Myrinthus can use its reaction to teleport up to 30 feet to an unoccupied space it can see and become invisible until the end of its next turn.

Quick Guise. Myrinthus makes one Grasping Hand attack or moves up to half its speed without provoking opportunity attacks.

Confounding Wink. Myrinthus targets one creature it can see within 120 feet. The target must succeed on a DC 22 Wisdom saving throw or have disadvantage on its next attack roll or saving throw before the end of its next turn.

Mask Swap (Costs 2 Actions). Myrinthus swaps faces with a creature it can see within 60 feet. The target and Myrinthus exchange appearances (the target takes on Myrinthus’s visage and Myrinthus takes the target’s) for 1 minute. The target is stunned until the end of its next turn as its senses recalibrate.