Boss Barbed Devil

Barbed Hide. At the start of each of its turns, the devil deals 5 (1d10) Piercing damage to any creature it is grappling or any creature grappling it.

Diabolical Restoration. If the devil dies outside the Nine Hells, its body disappears in sulfurous smoke, and it gains a new body instantly, reviving with all its Hit Points somewhere in the Nine Hells.

Magic Resistance. The devil has Advantage on saving throws against spells and other magical effects.

Multiattack. The devil makes one Claws attack and one Tail attack, or it makes two Hurl Flame attacks.

Claws. Melee Attack Roll: +5, reach 5 ft. Hit: 7 (2d6) Piercing damage. If the target is a Large or smaller creature, it has the Grappled condition (escape DC 13) from both claws.

Tail. Melee Attack Roll: +5, reach 10 ft. Hit: 11 (2d8) Slashing damage.

Hurl Flame. Ranged Attack Roll: +1, range 150 ft. Hit: 14 (4d6) Fire damage. If the target is a flammable object that isn’t being worn or carried, it starts burning.

At the end of it's turn, the boss barbed devil may begin one battlefield action.

Explosive meatballs. The boss spawns up to two lemures, max of 2 on field, and a single barb on the boss grows rapidly and begins pulsing along with the lemures. At the start of the boss' next turn, any lemure alive explodes. Every creature in a 10ft radius must take a dc 15 dex saving throw. On failure they take 4d6 fire damage. On success they take 2d6 fire damage. If the barb is removed before the start of its turn, it will take an extra 2d6 damage and the attack is cancelled

Tail Slam. The boss raises its tail above its head, aimed at the last creature alive that damaged it. If hit the boss will change targets to the creature who last attacked it. At the start of the boss' next turn, its tail slams down and everything in a 15ft cone has to make a dc 13 dex saving throw. On failure, take 3d10 piercing damage. on success, take 1d10 piercing damage.

When using a battlefield action, the Boss Barbed Devil cannot benefit from attacks of opportunity.