Asmodeus

Large Fiend (Devil), Lawful Evil

AC: 22

Initiative: +5 (15)

HP: 725 (50d10 + 450)

Speed: 30 ft., fly 120 ft. (hover)

STR: 30 (+10)
DEX: 21 (+5)
CON: 28 (+9)
INT: 25 (+7)
WIS: 30 (+10)
CHA: 30 (+10)

Saving Throws: Str +19, Con +18, Int +16, Cha +19

Skills: Arcana +16, Deception +28, Insight +28, Intimidation +19, Perception +19, Persuasion +19, Religion +16

Resistances: cold

Immunities: fire; poison; bludgeoning, piercing, slashing from nonmagical attacks that aren't silvered

Condition Immunities: blinded; charmed; frightened; paralyzed; poisoned; stunned

Senses: darkvision 120 ft., truesight 60 ft., Passive Perception 29

Languages: all, telepathy 120 ft.

CR: 30 (XP 155,000; PB +9)

Antimagic Aura.

Asmodeus has advantage on saving throws against spells and other magical effects. Spells of level 4 or lower can't damage Asmodeus.

Fiendish Regeneration.

Asmodeus regains 40 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. Asmodeus dies only if he starts his turn with 0 hit points and doesn't regenerate. If Asmodeus dies, his body regenerates, returning to life 13 (2d12) days later.

Legendary Resistance (3/Day).

If Asmodeus fails a saving throw, he can choose to succeed instead.

Submission Aura.

When a creature moves to be within 120 feet of Asmodeus, they must succeed on a DC 24 Wisdom saving throw or have the frightened condition until they leave the aura. While frightened, creatures kneel before Asmodeus, taking no actions unless he commands otherwise. If Asmodeus deals damage to a kneeling creature, the creature's frightened condition ends. A creature that succeeds the saving throw is immune to this effect for 1 hour.

Spellcasting.

Asmodeus casts one of the following spells, requiring no material components and using Wisdom as the spellcasting ability (spell save DC 27):

At will: Bane, Bestow Curse, Command, Cure Wounds, Darkness, Lesser Restoration, Remove Curse

1/day each: Antimagic Field, Earthquake, Flame Strike, Gate, Heal, Mass Heal, Wish

Actions

Multiattack.

Asmodeus makes four attacks using Ruby Rod, Chilling Gaze, or a combination of the two. He can replace one of the attacks with Hellish Smite.

Ruby Rod.

Melee Weapon Attack: +21 to hit, reach 5 ft., one target. Hit: 21 (2d8 + 12) necrotic damage, which also reduces the target's hit point maximum by the damage taken. This damage can't reduce a target's hit point maximum below 1. Any effect that removes a disease allows a creature's hit point maximum to return to normal.

Chilling Gaze.

Ranged Spell Attack: +16 to hit, range 60 ft., one target. Hit: 18 (2d10 + 7) cold damage, and the target has a-1 penalty to all attack rolls they make until the end of their next turn. This penalty can stack.

Hellish Smite.

Asmodeus targets a creature he can see within 300 feet of him, calling down a bolt of hellish lightning. The target must make a DC 24 Dexterity saving throw, taking 14 (4d6) lightning damage plus 14 (4d6) fire damage on a failed save, or half as much damage on a successful one.

Infernal Word: Stun (Recharge 4-6).

Asmodeus targets a creature he can see within 120 feet of him. The target must make a DC 24 Intelligence saving throw, taking 45 (10d8) force damage on a failed save, or half as much damage on a successful one. A creature that failed the save is stunned for up to 1 minute. The stunned creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success, but taking the damage again on a failed save.

Hell-Lord's Suggestion (Recharge 5-6).

Asmodeus targets a creature he can see within 120 feet of him. The target must make a DC 24 Charisma saving throw, taking 44 (8d10) psychic damage on a failed save, or half as much damage on a successful one. A creature that failed the save has the charmed condition for up to 1 minute. While charmed, a creature is controlled by Asmodeus, performing only actions that he suggests. A charmed creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success, but taking the damage again on a failed save.

Fires of the Nine Hells (Recharge 5-6).

Asmodeus chooses a point he can see within 500 feet of him, which explodes into a roaring inferno. All creatures within a 60-foot-radius sphere centered on that point must make a DC 24 Dexterity saving throw, taking 70 (20d6) fire damage on a failed save, or half as much damage on a successful one.

Reactions

Ruby Absorption.

As a reaction to being the sole target of a spell, Asmodeus can attempt to absorb the spell into the Ruby Rod.

Asmodeus rolls (1d20 + 2), and if the result is higher than (10 + spell level), the spell is absorbed into the rod and has no effect.

Legendary Actions

Legendary Action Uses: 3. Immediately after another creature's turn, this creature can expend a use to take one of the following actions; it regains all expended uses at the start of each of its turns.

Channel Ruby Rod.

The Ruby Rod has 66 charges. Asmodeus may spend its charges to cast one of the following spells from it, with a spell save DC of 20: Lesser Restoration (3 charges), Wall of Force (7 charges), Greater Restoration (12 charges), Chain Lightning (15 charges), Prismatic Spray (23 charges), Globe of Invulnerability (33 charges)

Strike (Costs 2 Actions).

Asmodeus makes a Ruby Rod attack.

Call Underling (Costs 3 Actions).

Asmodeus summons an allied pit fiend in an unoccupied space that he can see.

Lair Actions

On initiative count 20 (losing initiative ties), Asmodeus can take one lair action to cause the following effect or one from the archdevil lair action list (page 214); he can't take the same lair action two rounds in a row:

Cleansing Flame.
Asmodeus selects one spell effect on himself or a creature of his choice within 60 feet. That spell effect is removed.

Attack.
The archdevil uses one of their available melee or ranged attacks against a single foe.
Cast a Spell.
The archdevil uses their Spellcasting feature to cast an available spell. If the spell normally requires concentration, it lasts for the full duration instead.
Deceitful Whispers.
The archdevil whispers to a creature they can see within 30 feet. The target must make a DC 22 Wisdom saving throw. On a failed save, the target has the charmed condition until the start of their next turn and must use their reaction immediately to make an attack against one of the archdevil's enemies, chosen by the archdevil.
Fiendish Fortitude.
The archdevil recharges one of their expended abilities.
Frenzy.
The archdevil casts Haste on themself. The effect ends at initiative count 20 of the next round.
Summon Underlings.
The archdevil summons allied devils. The devils summoned depends on the archdevil using this feature. The summoned devils appear in unoccupied spaces which the archdevil can see. The Summoned Underlings table shows which devils each archdevil can summon.
Teleport.
The archdevil teleports themself to an area they can see within 120 feet.
Trap.
The archdevil casts the Hold Monster spell.

Regional Effects

The region containing Asmodeus's lair is corrupted by his presence, which creates the following effect:

The Devil's Greeting.
Within 500 miles of his lair, an illusory version of Asmodeus (as if he has cast the Project Image spell) appears. Asmodeus attempts to communicate with any characters and decipher their intentions. If they're hostile, Asmodeus pretends to prepare himself for combat, in an effort to make the character's waste their resources.

If Asmodeus dies, the effects fade over the course of 1d10 days.

Find this creature in the encounter builder

Source: Chains of Asmodeus, p. 217 - Licenses and attribution