Large fiend (demon), chaotic evil

Armor Class 18 (natural armor)
Hit Points 184 (16d10 + 96)
Speed 20 ft., fly 30 ft.

STR	DEX	CON	INT	WIS	CHA
21 (+5)	10 (+0)	22 (+6)	19 (+4)	12 (+1)	15 (+2)

Saving Throws Con +11, Int +9, Wis +6, Cha +7
Skills 
Damage Resistances cold, fire, lightning; bludgeoning, piercing, and slashing from nonmagical attacks
Damage Immunities poison
Condition Immunities poisoned
Senses truesight 120 ft., passive Perception 11
Languages Abyssal, telepathy 120 ft.
Challenge 13 (10000 XP)

Magic Resistance. The nalfeshnee has advantage on saving throws against spells and other magical effects.

Actions

Multiattack. The nalfeshnee uses Horror Nimbus if it can. It then makes three attacks: one with its bite and two with its claws.

Bite. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 32 (5d10 + 5) piercing damage.

Claw. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 15 (3d6 + 5) slashing damage.

Horror Nimbus (Recharge 5–6). The nalfeshnee magically emits scintillating, multicolored light. Each creature within 15 feet of the nalfeshnee that can see the light must succeed on a DC 15 Wisdom saving throw or be frightened 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 or the effect ends for it, the creature is immune to the nalfeshnee’s Horror Nimbus for the next 24 hours.

Teleport. The nalfeshnee magically teleports, along with any equipment it is wearing or carrying, up to 120 feet to an unoccupied space it can see.