Large fiend, lawful evil
Armor Class 20 (natural)
Hit Points 504 (28d10 + 224)
Speed 50 ft., fly 100 ft.
STR 28 (+9) DEX 20 (+5) CON 26 (+8) INT 24 (+7) WIS 22 (+6) CHA 28 (+9)
Saving Throws Str +17, Dex +13, Con +16, Wis +14, Cha +17
Skills Deception +25
Damage Resistances acid, cold, lightning
Damage Immunities fire, poison; bludgeoning, piercing, and slashing from nonmagical weapons
Condition Immunities poisoned
Senses truesight 120 ft., passive Perception 16
Languages Abyssal, Draconic, Infernal, telepathy 500 ft.
Challenge 26 (100,000 XP)
Legendary Resistance (3/day). If the infernal fails a saving throw, it can choose to succeed instead.
Magic Resistance. The infernal has advantage on saving throws against spells and other magical effects.
Magic Weapons. The infernal's weapon attacks are magical.
Spell Reflection If both of an infernal's saving throws against magic (due to its resistance) are successful, the spell is reflected upon the caster.
Innate Spellcasting. The infernal's spellcasting ability is Charisma (spell save DC 25). The infernal can innately cast the following spells, requiring no material components:
Constant – nondetection
At will: detect magic, disguise self, dispel magic, fireball, power word stun, telekinesis, teleport
3/day each: animate dead, dominate monster, hold monster, implosion, wall of fire
Multiattack. The infernal makes four attacks: one with its bite, two with its claws, and one with its tail.
Bite. Melee Weapon Attack: +17 to hit, reach 5 ft., one target. Hit: 27 (4d8 + 9) piercing damage. The target must succeed on a DC 25 Intelligence saving throw or lose its highest available spell slot and the infernal recharges an expended innate spell of that level or lower.
Claw. Melee Weapon Attack: +17 to hit, reach 10 ft., one target. Hit: 22 (3d8 + 9) slashing damage and 22 (4d10) necrotic damage.
Tail. Melee Weapon Attack: +17 to hit, reach 10 ft., one target. Hit: 31 (4d10 + 9) bludgeoning damage.
Hellball (Recharge: 6) The infernal hurls a magical ball of black flames that explodes at a point it can see within 300 feet of it. Each creature in a 40-foot radius sphere centered on that point must make a DC 25 Dexterity saving throw. The sphere spreads around corners. A creature takes 35 (10d6) acid damage, 35 (10d6) fire damage, 35 (10d6) poison damage and 35 (10d6) necrotic damage on a failed save, or half as much damage on a successful one.
An infernal can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The infernal regains spent legendary actions at the start of its turn.
Call Fiends. The infernal summons two pit fiends. If it uses this ability multiple times, the previous fiends return from whence they came.
Constrict. The infernal makes a tail attack against one foe in reach. If successful, the creature must succeed on a Strength saving throw DC 25 or become restrained. The infernal's tail attack can only target the restrained creature, but it can end the effect at any time.
Blasphemy. (Costs 3 actions) The infernal speaks a word of black power. All good aligned creatures within 60 ft. must succeed on a Wisdom saving throw DC 25 or take 35 (10d6) thunder damage and be stunned for one round. They take half damage on a successful save.