Pit Fiend
Large Fiend (devil), lawful evil
25,000 XP
Special Abilities
Fear Aura
Any creature hostile to the pit fiend that starts its turn within 20 feet of the pit fiend must make a DC 21 Wisdom saving throw, unless the pit fiend is incapacitated. On a failed save, the creature is frightened until the start of its next turn. If a creature's saving throw is successful, the creature is immune to the pit fiend's Fear Aura for the next 24 hours.
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
Actions
Multiattack
The pit fiend makes four attacks: one with its bite, one with its claw, one with its mace, and one with its tail.
Bite
Melee Weapon Attack: +14 to hit, reach 5 ft., one target. Hit: 22 (4d6 + 8) piercing damage. The target must succeed on a DC 21 Constitution saving throw or become poisoned. While poisoned in this way, the target can't regain hit points, and it takes 21 (6d6) poison damage at the start of each of its turns. The poisoned target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
Claw
Melee Weapon Attack: +14 to hit, reach 10 ft., one target. Hit: 17 (2d8 + 8) slashing damage.
Mace
Melee Weapon Attack: +14 to hit, reach 10 ft., one target. Hit: 15 (2d6 + 8) bludgeoning damage plus 21 (6d6) fire damage.
Tail
Melee Weapon Attack: +14 to hit, reach 10 ft., one target. Hit: 24 (3d10 + 8) bludgeoning damage.
Quick Reference
Running This Encounter
A Pit Fiend is a legendary creature that demands respect and preparation from even high-level parties. Use its lair actions to control the battlefield, forcing difficult decisions each round. Leverage its intelligence by having it cast spells strategically before closing into melee combat. Consider surrounding the party with summoned creatures or minions to create action economy challenges.
Combat Tactics
The Pit Fiend opens with damaging spells like fireball or cone of cold, then uses its frightful presence to break cohesion. It prioritizes eliminating spellcasters while using legendary actions to maintain control, retreating when bloodied and using its innate spellcasting to frustrate pursuits. It may negotiate or demand surrender if outmatched, preferring to escape rather than fight to the death.
Environment & Setting
Place the Pit Fiend in a volcanic lair, infernal temple, or abyssal citadel filled with lava pits, pillars, and hazardous terrain. The environment should provide cover and elevation changes to maximize the fiend's mobility advantage over typical adventurers.