Innate Spellcasting. Xyl'Rioh's innate spellcasting ability is Charisma (spell save DC 20). Xyl'Rioh's can innately cast the following spells, requiring no material components:

At will: alter self, darkness, heat metal, invisibility (self only), magic missile

Legendary Resistance: (3/Day) If Xyl'Rioh fails a saving throw, It can choose to pass instead.

Magic Resistance. Xyl'Rioh's  has advantage on saving throws against spells and other magical effects.

Magic Weapons. TXyl'Rioh's  weapon attacks are magical.

Spellcasting. Xyl'Rioh  is a 16th-level spellcaster. Its spellcasting ability is Intelligence (spell save DC 17, +9 to hit with spell attacks). Xyl'Rioh has the following wizard spells prepared:

Cantrips (at will): fire bolt, mage hand, minor illusion, prestidigitation

1st level (4 slots): detect magic, identify, shield, Fog Cloud

2nd level (3 slots): detect thoughts, Crown of Madness, phantasmal force, suggestion

3rd level (3 slots): counterspell, fear, Stinking Cloud

4th level (3 slots): Evard's Black Tentacles, dimension door

5th level (2 slots): contact other plane, Cone of Cold

6th level (1 slot): Eyebite

7th level (1 slot): finger of death

8th level (1 slot): Power Word Stun

Claws. Melee Weapon Attack: +17 to hit, reach 5 ft., one target. Hit: 17 (2d12 + 5) slashing damage. The target must make a DC 24 Constitution saving throw, taking 18 (6d6) poison damage on a failed save, or half as much damage on a successful one.

Teleport. Xyl'Rioh magically teleports, along with any equipment it is wearing or carrying, up to 60 feet to an unoccupied space it can see.

Xyl'Rioh can take 3 legendary actions, choosing from the options below. Only one legendary action can be used at a time and only at the end of another creature's turn. Xyl'Rioh regains one legendary action at the start of It's turn.

Attack: Melee Weapon Attack: +17 to hit, reach 5 ft., one target. Hit: 17 (2d12 + 5) slashing damage. The target must make a DC 24 Constitution saving throw, taking 18 (6d6) poison damage on a failed save, or half as much damage on a successful one.

Shadow Walk: Xyl'rioh can teleport to any area of darkness it can see.

Ghastly Gaze: Xyl'Rioh can target one creature it can see that just attacked it, and force it to make a DC20 Charisma save or become frightened for 1 minute. The creature can repeat the saving throw at the start of each of it's turns.