Large fiend, lawful evil

Armor Class: 21

Hit Points: 337

Speed: 30 ft , fly: 60 ft

STR

26 +8

DEX

14 +2

CON

24 +7

INT

22 +6

WIS

18 +4

CHA

24 +7

Saving Throws: DEX +8, WIS +10

Skills: Perception +10, Persuasion +19

Damage Resistances: Cold

Damage Immunities: Fire, Poison

Condition Immunities: Poisoned

Senses: Truesight 120ft., Passive Perception 20

Languages: Infernal, Telepathy 120ft.

Challenge Rating: 20 ( 25000 XP)

Proficiency Bonus: +6

Actions

Multiattack. The pit fiend makes one Bite attack, two Devilish Claw attacks, and one Fiery Mace attack.   Bite. Melee Attack Roll: +14, reach 10 ft. Hit: 18 (3d6 + 8) Piercing damage. If the target is a creature, it must make the following saving throw. Constitution Saving Throw: DC 21. Failure: The target has the Poisoned condition. While Poisoned, the target can’t regain Hit Points and takes 21 (6d6) Poison damage at the start of each of its turns, and it repeats the save at the end of each of its turns, ending the effect on itself on a success. After 1 minute, it succeeds automatically.   Devilish Claw. Melee Attack Roll: +14, reach 10 ft. Hit: 26 (4d8 + 8) Necrotic damage.   Fiery Mace. Melee Attack Roll: +14, reach 10 ft. Hit: 22 (4d6 + 8) Force damage plus 21 (6d6) Fire damage.   Hellfire Spellcasting (Recharge 4–6). The pit fiend casts Fireball (level 5 version) twice, requiring no Material components and using Charisma as the spellcasting ability (spell save DC 21). It can replace one Fireball with Hold Monster (level 7 version) or Wall of Fire.