Bone Devil is a Large fiend with lawful evil alignment and Challenge Rating 9 in the 2014 SRD. This stat block includes AC 19, 142 hit points, speeds, traits, and 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.