Geryon

Huge Fiend (devil), Lawful Evil

Armor Class 19 (natural armor)

Hit Points 300 (24d12 + 144)

Speed 30 ft., fly 50 ft.

STR

DEX

CON

INT

WIS

CHA

Saving Throws DEX +10, CON +13, WIS +10, CHA +13

Skills Deception +13, Intimidation +13, Perception +10

Damage Resistances bludgeoning, piercing, slashing, from nonmagical attacks that aren't silvered

Damage Immunities cold, fire, poison

Condition Immunities Charmed, Exhaustion, Frightened, Poisoned

Senses truesight 120 ft., passive Perception 20

Languages all, telepathy 120 ft.

Challenge 22 (41,000 XP)

Traits

Legendary Resistance (3/Day). If Geryon fails a saving throw, he can choose to succeed instead.

Magic Resistance. Geryon has advantage on saving throws against spells and other magical effects.

Regeneration. Geryon regains 20 hit points at the start of his turn. If he takes radiant damage, this trait doesn't function at the start of his next turn. Geryon dies only if he starts his turn with 0 hit points and doesn't regenerate.

Spellcasting

Spellcasting. Geryon casts one of the following spells, requiring no material components and using Charisma as the spellcasting ability (spell save DC 21):

At will: alter self (can become Medium when changing his appearance), detect magic, ice storm, invisibility (self only), locate object, suggestion, wall of ice

1/day: banishment

Actions

Multiattack. Geryon makes one Claw attack and one Stinger attack.

Claw. Melee Weapon Attack: +16 to hit, reach 15 ft., one target. Hit:23 (4d6 + 9) cold damage. If the target is Large or smaller, it is grappled (DC 24), and it is restrained until the grapple ends. Geryon can grapple one creature at a time. If the target is already grappled by Geryon, the target takes an extra 27 (6d8) cold damage.

Stinger. Melee Weapon Attack: +16 to hit, reach 20 ft., one creature. Hit:14 (2d4 + 9) force damage, and the target must succeed on a DC 21 Constitution saving throw or take 13 (2d12) poison damage and become poisoned until it finishes a short or long rest. The target's hit point maximum is reduced by an amount equal to half the poison damage taken. This reduction lasts until the poisoned condition is removed. The target dies if its hit point maximum is reduced to 0.

Teleport. Geryon teleports, along with any equipment he is wearing and carrying, up to 120 feet to an unoccupied space he can see.

Legendary Actions

Infernal Glare. Geryon targets one creature he can see within 60 feet of him. The target must succeed on a DC 23 Wisdom saving throw or become frightened of Geryon until the end of its next turn.

Teleport. Geryon uses Teleport.

Swift Sting (Costs 2 Actions). Geryon makes one Stinger attack.

Lore

Geryon is locked in an endless struggle with Levistus for control of Stygia. The two have fought for centuries, each displacing the other innumerable times. Currently, Levistus claims lordship over Stygia, but he has been trapped in an enormous block of ice at the command of Asmodeus. In response, Geryon is marshaling his followers, hoping to use this opportunity to replace his hated rival.