Mammon, Lord of the Third

Mammon huge fiend (devil), lawful evil

Armor Class 22 (natural armor)

Hit Points 525 (42d12 + 252)

Speed 60 ft., swim 30 ft.

STR 24/+7

DEX 20/+5

CON 22/+6

INT 28/+9

WIS 20/+5

CHA 29/+9

Saving Throws Strength +15, Constitution +14, Charisma +17, Intelligence +17

Skills Perception +21, Deception +17, Insight +13, Intimidation +17

Damage Resistances Cold; Lightning; Bludgeoning, Piercing, and Slashing from Nonmagical attacks that aren't silvered

Damage Immunities Poison, Fire

Condition Immunities Poisoned, Charmed, Frightened, Exhaustion

Senses Blindsight 30 ft., Truesight 120 ft., Passive Perception 31

Languages All languages, telepathy 150 ft.

Proficiency Bonus +8

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

Magic Weapons. All of Mammon’s weapon attacks count as magical

Regeneration. Mammon regains 30 hit points at the start of his turn. If he takes radiant damage before that this trait doesn't function. He can only die if he starts his turn with 0 hit points and can't regenerate.

Legendary Resistance (3/day). When Mammon fails a saving throw, he can choose to succeed instead.

Actions

• Multiattack. Mammon uses Terrifying Presence then attacks with Constrict, Bitterspear, then Bite. Or he uses Terrifying Presence then casts a spell and makes one melee attack.
• Bite. Melee Weapon Attack: +15 to hit, reach 10 ft., one target. Hit: 21 (4d6 + 7) piercing damage. The target must succeed on a DC 22 Constitution saving throw or become poisoned. While poisoned in this way, the target can't regain hit points, and its hit point maximum is reduced by 21 (6d6) 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.
• Constrict (Archdevil form only). Melee Weapon Attack: +15 to hit, reach 15 ft., one Large or smaller creature. Hit: 16 (3d6 + 7) bludgeoning damage plus 14 (4d6) poison damage, and the target is grappled (escape DC 16). Until this grapple ends, the target is restrained and takes 17 (3d6 + 7) bludgeoning damage plus 14 (4d6) poison damage at the start of each of its turns, and the devil can’t constrict another target.
• Bitterspear. Melee Weapon Attack: +18 to hit, reach 15 ft., one creature. Hit: 22 (3d6+10) if used with one hand or 25 (3d8+10) piercing damage when used with two hands. Any creature hit must make a DC 25 Wisdom save or be driven berserk. A creature driven berserk is charmed by Mammon and hostile to every other creature that it can see.
• Terrifying Presence. Each creature of the devil's choice that is within 120 feet of the dragon and aware of it must succeed on a DC 25 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to Mammon’s Terrifying Presence for the next 24 hours.
• Innate Spellcasting (Pit Fiend and Archdevil form). Mammon’s innate spellcasting ability is Charisma (spell save DC 25). He can innately cast the following spells, requiring no material components:
• At will: magic aura, suggestion, alter self (can become Medium sized), detect magic, dispel magic, staggering smite
• 3/day each: firestorm, teleport, compulsion, banishment, slow, legend lore
• 1/day: divine word, symbol (hopelessness only), dominate monster, mass suggestion, harm,

Bonus Actions

• Shape change. Mammon can transform into a pit fiend, or back into its true form. Its physical statistics match the pit fiend but he maintains his Innate Spellcasting feature, Legendary Resistances, Proficiencies, Wisdom, Intelligence, and Charisma scores. Any equipment he is wearing or carrying is transformed.
• Devil Summoning (1/day). The Lord of the Third summons 3d4 bearded devils, 1d6 bone devils, or 1 pit fiend. A summoned devil obeys Mammon’s telepathic commands (no action required), can't summon other devils, and remains until it dies, or Mammon dismisses them as an action.

Legendary Actions

Mammon can take up to 3 Legendary Actions that return at the start of his turn. He can only take Legendary Actions at the end of another creature's turn.

Bitterspear. Mammon makes one attack with Bitterspear against every creature in range.

Tax Collection (2 Actions). Mammon tries to take all of a creature's currency. One creature within 20-feet must make a DC 21 Charisma saving throw. If it fails, every coin of the highest value instantly transports to the Archdevil's bag of holding.

Lair Actions

On initiative count 20 (losing initiative ties), the devil takes a lair action to cause one of the following effects, the dragon can’t use the same effect two rounds in a row:

Pools of water that the devil can see within 120 feet of it surge outward in a grasping tide. Any creature on the ground within 20 feet of such a pool must succeed on a DC 15 Strength saving throw or be pulled up to 20 feet into the water and knocked prone.

A cloud of swarming insects fills a 20-foot-radius sphere centered on a point Mammon chooses within 120 feet of it. The cloud spreads around corners and remains until the devil dismisses it as an action, uses this lair action again, or dies. The cloud is lightly obscured. Any creature in the cloud when it appears must make on a DC 15 Constitution saving throw, taking 10 (3d10) piercing damage on a failed save, or half as much damage on a successful one. A creature that ends its turn in the cloud takes 10 (3d10) piercing damage.