Valg Prince

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

Spellcasting. The Valg prince is a 10th-level spellcaster. Its spellcasting ability is Intelligence (spell save DC 14, +6 to hit with spell attacks). The Valg prince has following wizard spells prepared:
Cantrips (at will): mage hand, minor illusion 
1st level (4 slots): cause fear, mage armor, shield
2nd level (3 slots): darkness, misty step 
3rd level (3 slots): fear, vampiric touch
4th level (3 slots): private sanctum 
5th level (2 slots): cloudkill

Longsword. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 9 (1d8 + 4) slashing damage, or 10 (1d10 + 4) piercing damage if used with two hands to make a melee attack.

Display Fear. Each creature that comes within 10 feet of the Valg prince must succeed on a DC 16 Wisdom saving throw or take 15 (3d8) 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 prince's Display Fear for the next 24 hours.