Valg Queen

Valg Royalty. The Valg queen has advantage on saving throws against being charmed, and magic can't put the Valg queen to sleep.

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

Spellcasting. The Valg queen is an 19th-level spellcaster. Its spellcasting ability is Intelligence (spell save DC 19, +11 to hit with spell attacks). The Valg queen has the following wizard spells prepared:

Cantrips (at will): chill touch, mage hand, minor illusion, ray of frost (darkness)

1st level (4 slots): absorb elements, cause fear, longstrider, shield

2nd level (3 slots): alter self, darkness, mind spike, misty step

3rd level (3 slots): counterspell, fear, fly, vampiric touch

4th level (3 slots): banishment, blight, fire shield (cold), phantasmal killer

5th level (3 slots): enervation, far step, telekinesis, wall of force

6th level (2 slots): circle of death, mental prison

7th level (1 slot): finger of death

8th level (1 slot): maddening darkness

9th level (1 slot): foresight

Longsword. Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: 19 (2d8 + 10) slashing damage, or 21 (2d10 + 10) piercing damage if used with two hands to make a melee attack.

Dark Whip. Melee Weapon Attack: +11 to hit, reach 30 ft. one target. Hit:  17 (2d6 + 10) slashing damage and the target must succeed on a DC 20 Strength saving throw or be pulled 25 feet toward the Valg queen.

Display Fear. Each creature that comes within 10 feet of the Valg queen must succeed on a DC 19 Wisdom saving throw or take 20 (4d8) psychic damage and become Stunned for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful, the creature takes half damage and is not Stunned. On a successful save or the effect ends for it, the creature is immune to the Valg queen's Display Fear for the next 24 hours.

Umbrakinesis. The Valg queen manipulates the darkness surrounding her to coalesce into a wall of darkness. The Valg queen adds +2 to its AC against one attack that would hit her.

The Valg queen can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The Valg queen regains spent legendary actions at the start of its turn.

Dark Whip Attack (1 action). The Valg queen makes one whip attack.

Umbrastep (2 actions). The Valg queen possesses the ability to manipulate darkness and shadows and thus steps into her own shadow and reappears out of another shadow in sight of the original position and within 60 ft. 

Mind Manipulation (3 actions). The Valg queen penetrates the mind of her target and begins combing through the target's worst memories, forcing the target to relive each one. The target must succeed on a DC 19 Intelligence saving throw or take 30 (10d6) psychic damage and is Stunned for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.