Ultroloth

Armor Class 19 (natural armor)
Hit Points 153 (18d8 + 72)
Speed 30 ft., fly 60 ft.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)