Crimson Scale Pit Fiend

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

Magic Weapons. The pit fiend's weapon attacks are magical.

Innate Spellcasting. The pit fiend's spellcasting ability is Charisma (spell save DC 21). The pit fiend can innately cast the following spells, requiring no material components:

At will: detect magic, fireball

3/day each: hold monster, wall of fire, [/spell]meteor swarm.

Multiattack. The pit fiend makes four attacks: one with its bite, one with its claw, one with its mace, and one with its fire breath.

Bite. Melee Weapon Attack: +14 to hit, reach 5 ft., one target. Hit: 52 (8d6 + 8) piercing damage plus 10 fire damage.

Claw. Melee Weapon Attack: +14 to hit, reach 10 ft., one target. Hit: 37 (4d8 + 8) slashing damage.

Mace. Melee Weapon Attack: +14 to hit, reach 10 ft., one target. Hit: 35 (5d6 + 12) bludgeoning damage plus 41 (6d6+9) fire damage.

Fire Breath. Ranged Weapon Attack: +3 to hit, range 150/600 ft., one target. Hit: 84 (12d6 + 13)  fire damage.