Cthulhu | Colossal Threat for Fifth Edition (Updated 7/29/19)

This is a preview of Cthulhu for Fifth Edition. If you’d like a printable PDF of this stat-block Cthulhu, head over to my Patreon.

Great Cthulhu is nightmare made flesh, towering well over 1,000 feet high. His head appears as an octopus or squid, with writhing lengths of tentacle reaching 100 feet or more. His body is a corpulent slab of slime-kissed flesh, generally humanoid except for his enormous size and terrible claws on his hands and feet. Great batlike wings grow from his back, useful both in the air and in the water. Cthulhu dwells in the corpse city of primordial R’lyeh, sunken deep beneath the surface of the Pacific. He lies in a deathlike trance, but someday the city will rise and he will wake. When he does, let the world weep, for his hunger is an entity unto itself, and will not be slaked.”

In the city are also entombed other creatures of primordial ancestry, creatures who arc possibly members of Cthulhu’s race, though none have taken on aspects of godhood, as Cthulhu has. Great Cthulhu is the high priest and ruler of them all and is by far the most potent.

Great Old One. Cthulhu is immortal. He does not require air, food, drink, or sleep.

Edits (7/29/2019): I made the following changes:

  • I removed the redundant regeneration traits. Only Cthulhu’s head now has regeneration.
  • I added a damage threshold to Cthulhu’s head.
  • Cthulhu can heal 100 hit points on any of his body parts using an action.
  • Added in two more actions for him to choose from.
  • I calculated the experience reward for Cthulhu.

[su_note note_color=”#efefef”]

Great Cthulhu

Colossal aberration (Great Old One), chaotic evil (1,000 ft. tall)

Travel Pace 8 miles per hour (192 miles per day)

Abilities Str 30 (+10), Dex 12 (+1), Con 30 (+10), Int 30 (+10), Wis 27 (+8), Cha 29 (+9)

Saving Throws Str +19, Dex +10, Con +19, Int +19, Wis +17, Cha +18

Skills Arcana +19, Insight +17, Religion +19, Perception +26

Damage Immunities acid, cold, fire, lightning, poison, necrotic, thunder; bludgeoning, piercing, and slashing from nonmagical weapons

Condition Immunities charmed, frightened, paralyzed, petrified, poisoned, stunned

Senses truesight 5 miles, passive Perception 36

Languages all, telepathy 5 miles

Challenge special (465,000 XP)

Demigod. Cthulhu makes all ability checks, attack rolls, and saving throws with advantage. If Cthulhu rolls a 1 while making an attack, it does not count a critical failure. In addition, all of Cthulhu’s senses extend up to five miles.

Immutable Form. Cthulhu is immune to any spell or effect that would alter his form.

Limited Magic Immunity. Cthulhu can’t be affected or detected by spells of 6th level or lower unless he wishes to be. Cthulhu has advantage on saving throws against all other spells and magical effects.

Regeneration. Each of Cthulhu’s components regains 50 hit points at the start of his turn. If a component takes radiant damage, this trait doesn’t function at the start of Cthulhu’s next turn. Cthulhu dies only if his head has 0 hit points at the start of his turn and doesn’t regenerate.

Remote Sensing. Cthulhu can perceive anything within 5 miles of one of his worshippers, a creature charmed by him, or a creature that speaks his name, as well as any of his holy sites or objects.

Siege Monster. Cthulhu’s attacks deal double damage to objects and structures.

Unspeakable Presence. Any creature that starts its turn within 500 feet of Cthulhu and is aware of him must make a DC 26 Wisdom saving throw. On a failed saving throw, a creature takes 21 (4d10) psychic damage and becomes permanently frightened of Cthulhu. Only a greater restoration spell or similar madness-curing effect can end this frightened effect. On a successful saving throw, a creature is frightened of Cthulhu until the end of its next turn, after which the creature is immune to Cthulhu’s Unspeakable Presence for 1 hour.

Actions and Legendary Actions

On his turn, Cthulhu can take 3 actions, choosing from the options below.

In addition, Cthulhu can take 3 legendary actions, choosing from the same options. Only one legendary action can be used at a time and only at the end of another creature’s turn. Cthulhu regains spent legendary actions at the start of his turn.

Claws. Cthulhu attacks with his claws.

Heal. Cthulhu uses his head to heal himself.

Magical Attack (Costs 3 Actions, 1/Round). Cthulhu uses his head to make a magical attack.

Move. Cthulhu uses his head to move with his feet or his wings.

Non-Attack Action. Cthulhu can take the Disengage, Dodge, Help, Hide, Search, or Use an Object action.

Spell. Cthulhu uses his head to cast one of his innate spells.

Tentacles. Cthulhu attacks with up to three of his tentacles.

Cthulhu’s Body

Armor Class 25 (natural armor)

Hit Points 5,000 (threshold 100)

Control & Weapons: Cthulhu’s Head

Armor Class 25 (natural armor)

Hit Points 500 (threshold 20)

Heal: One of Cthulhu’s components regains 100 hit points.

Innate Spellcasting: Cthulhu’s innate spellcasting ability is Intelligence (spell save DC 27). He can innately cast the following spells, requiring no components:

  • At will: control water, control weatherdetect evil and good, detect magic, plane shift (self only), sendingteleport

Magical Attack: Cthulhu uses one of the following magical effects.

  • Enslave. Each creature of Cthulhu’s choice within 500 feet of him must succeed on a DC 27 Wisdom saving throw or become magically charmed by Cthulhu until Cthulhu dies or until he is on a different plane of existence from the target. The charmed target is under Cthulhu’s control and can’t take reactions, and Cthulhu and the target can communicate telepathically with each other over any distance. Only a remove curse spell or similar magic can end this effect on a creature.
  • Mind Blast. Cthulhu emits a torrent of psychic energy in a 1,000-foot cone. Each creature in the area must make a successful DC 27 Intelligence saving throw or take 120 (20d10 + 10) psychic damage and permanently fall unconscious. Only a greater restoration spell or similar magic can wake the unconscious creature from its slumber.
  • Psychic Drain. Up to three creatures charmed by Cthulhu must make a DC 27 Intelligence saving throw or die. Cthulhu regains hit points equal to the number of hit points the creature had remaining before it died.
  • Wave of Blight. Necromantic energy explodes from Cthulhu’s body, draining moisture and vitality from all living things around him. Each creature within 500 feet of Cthulhu must make a DC 27 Constitution saving throw. A target takes 110 (20d10) necrotic damage on a failed saving throw or half as much damage on a successful one. This magical attack has no effect on undead or constructs. Any plant or magical plant in the area makes the saving throw with disadvantage and the effect deals maximum damage to it. If a target is a nonmagical plant that isn’t a creature such as a tree or a shrub, it doesn’t make a saving throw; it simply withers and dies.

Movement: Move up to the speed of one of Cthulhu’s movement components.

Movement: Feet

Armor Class 25 (natural armor)

Hit Points 500 (threshold 20)

Speed (land) 60 ft.

Rampage. While moving, Cthulhu can enter a creature’s space and stop there. The first time he enters a creature’s space on his turn, that creature must make a DC 27 Strength or Dexterity saving throw (target’s choice). On a failed saving throw, the creature is knocked prone and takes 37 (5d10 + 10) bludgeoning damage plus 27 (5d10) necrotic damage. On a successful saving throw, a creature takes half as much damage and isn’t knocked prone.

Movement: Wings

Armor Class 19 (natural armor)

Hit Points 1,000 (threshold 30)

Speed (air) 120 ft.

Wing Blast. Whenever Cthulhu moves using his wings, each creature within 100 feet of Cthulhu at the start of his movement must succeed on a DC 27 Dexterity saving throw or take 31 (6d6 + 10) bludgeoning damage and be knocked prone.

Weapons: Claws (2)

Armor Class 25 (natural armor)

Hit Points 500 (threshold 20)

Special Melee Attack: Cthulhu swings one of his arms. Each creature in a 100-foot cube originating from Cthulhu’s body must make a DC 27 Strength or Dexterity saving throw (target’s choice). On a failure, a target takes 65 (10d10 + 10) bludgeoning damage plus 55 (10d10) necrotic damage and is flung up 500 feet away from Cthulhu in a direction of Cthulhu’s choice and knocked prone. If a thrown target strikes an object, such as a wall or floor, the target takes 3 (1d6) bludgeoning damage for every 10 feet it was thrown to a maximum of 20d6. If the target is thrown at another creature, that creature must succeed on a DC 27 Dexterity saving throw or take the same damage and be knocked prone.

If the saving throw is successful, the target takes half the damage and isn’t flung away or knocked prone.

In addition, unsecured objects that are completely within the area of effect are automatically flung 500 feet away from Cthulhu.

Weapons: Tentacles (10)

Armor Class 21 (natural armor)

Hit Points 100 (threshold 10)

Melee Weapon Attack: +19 to hit, reach 50 ft., one target. Hit: 37 (5d10 + 10) bludgeoning damage plus 37 (5d10 + 10) psychic damage plus 27 (5d10) necrotic damage. If the target is a creature, it is grappled (escape DC 20). Until the grapple ends, the target is restrained and takes 37 (5d10 + 10) psychic damage plus 27 (5d10) necrotic damage at the start of each of its turns and Cthulhu can’t use the same tentacle on another target.


Want a PDF of this?

This is a preview of Cthulhu for Fifth Edition. If you’d like a printable PDF of this stat-block Cthulhu, head over to my Patreon.

Is this overpowered? Hell yes, it is.

But hey, I wanted to do the big guy justice. So how do you beat something like Cthulhu? That’s totally up to you, the GM. Perhaps you can find the right ritual to banish him back to R’yleh. Or maybe you can drop a few nuclear warheads on his head? This sort of challenge is meant to be extremely difficult, beyond any tarrasque, lich, or worse.

Have fun!

Art by Baranger.


22 thoughts on “Cthulhu | Colossal Threat for Fifth Edition (Updated 7/29/19)

  1. Stating out any of the Great Old Ones is a bit like using a game of pictionary to explain particle physics. In other words, interesting but woefully inadequate.

    If you give something stats some munchkin is gonna make some min max monstrosity to beat it.

    IMO. The answer is—-in a stand up fight the big C wins, period. The end.

  2. The Demigod and Remote Sensing traits are kind of ridiculous- since actual 5E gods (Tiamat) have nothing of the sort.

    The challenge seems good, a high-level party that knows to go for the head instead of his body (AKA not Thor) should be able to take it down.

    1. Hey, thanks for the feedback!

      Comparing things to Tiamat usually doesn’t work since it was so early in 5e creation, I think possibly even before the official DMG and MM came out. Despite she being pretty powerful, the typical WotC approach to statting powerful beings is to simply not. There are a few post-Tiamat exceptions (Zariel, for one, and the demon lords), but the powers rarely get the treatment.

      This particular build of Big C pulls from d20 CoC’s stat block with all his goodies from that edition, and combines it with the new ship rules from GoSM. He’s a tough bugger, but yeah, you’re right. A wise party–with some great defensive capabilities–might be able to take him down.

      1. I don’t see how, he is 1000 feet tall, correct me if I’m wrong but it seems a bit difficult to find abilities with 700ish range to hit the bottom part of his head.

      2. How could any party reasonably defeat this as I is 1000 ft tall and they don’t have the range?

  3. Is the intention that you can destroy parts? Each part says it is only destroyed if his head or body is reduced to zero HP and doesn’t regenerate, except that’s also the same condition under which he dies.

      1. Hmm, if I understand you correctly, that’s a roundabout way of saying the parts continue to regenerate as long as he’s alive. Maybe the text should connect those dots for us.

      2. Yeah, I’ll take a look at it. My original thought was to make him regenerating his parts as a heavy-cost action.

      1. Im guessing I might need to alter it a bit if I truly want them to have a chance

      2. If your guys are level 20, they should be okay. Just make sure that they know what they’re facing before they do. Also, create a separate method for banishing him.

  4. I had an idea for something using this format said it out loud then you did it /:

  5. How could any pcs fight this beast. I mean if his head is ~1000 ft. in the air then he is effectively indestructible by standard means. Pretty cool overall though. Would be REALLY fun if you set up a campaign around this baddie and he is the final BBEG. I might even do that and use him. Time to get writing some plot hooks…

  6. My party has been teased with a great old one boss for the entire campaign, and I have been working on writing up a sufficiently heinous stat block. I will leak Big C’s abilities and stats through RP research made with appropriate sanity consequences.

    This is a boss whose appearance will herald the end of existence. They will be attempting to prevent his summoning/awakening that The Eldest and his kingdom of Aboleths have been planning for generations. If he arrives, even at level 20, they will be depleted and it will be Game Over.

    Having this stat block incrementally leaked will build up so much dread, I can almost feel it already!

    Thanks so much!!

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