Bone Devil

Large fiend (devil), lawful evil

Armor Class 19 (natural armor)
Hit Points 142 (15d10 + 60)
Speed 40 ft., fly 40 ft.

Saving Throws Int +5, Wis +6, Cha +7
Skills Deception +7, Insight +6
Damage Resistances cold; bludgeoning, piercing, and slashing from nonmagical attacks that aren't silvered
Damage Immunities fire, poison
Condition Immunities poisoned
Senses darkvision 120 ft., passive Perception 12
Languages Infernal, telepathy 120 ft.
Challenge 9 (5,000 XP)

Devil's Sight. Magical darkness doesn't impede the devil's darkvision.
Magic Resistance. The devil has advantage on saving throws against spells and other magical effects.

Actions

Multiattack. The devil makes three attacks: two with its claws and one with its sting.
Claw. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 8 (1d8 + 4) slashing damage.
Sting. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 13 (2d8 + 4) piercing damage plus 17 (5d6) poison damage, and the target must succeed on a DC 14 Constitution saving throw or become poisoned for 1 minute. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.