Ultroloth

Medium fiend (Yugoloth), neutral evil
Armor Class 19 (natural armor)
Hit Points 153 (18d8 + 72)
Speed 30 ft., fly 60 ft.
STR
16 (+3)
DEX
16 (+3)
CON
18 (+4)
INT
18 (+4)
WIS
15 (+2)
CHA
19 (+4)
Skills Intimidation +9, Perception +7, Stealth +8
Damage Resistances cold, fire, lightning; bludgeoning, piercing, and slashing from nonmagical attacks
Damage Immunities acid, poison
Condition Immunities charmed, frightened, poisoned
Senses truesight 120 ft., passive Perception 17
Languages Abyssal, Infernal, telepathy 120 ft.
Challenge 13 (10000 XP)
Innate Spellcasting.
Magic Resistance.
Magic Weapons.
Actions
Multiattack.
Longsword.
Hypnotic Gaze.
Teleport.

This full creature's stat block is not available (not OGL).

Monster Manual
Ultroloth