Epic Monsters: Cthulhu for D&D!

Epic Monsters: Cthulhu (5E)

Welcome to Epic Monsters, a complementary series to the Mythological Figures column! These are high challenge rating statblocks built to bring a grin to the faces of GMs and strike terror into the hearts of even the most experienced adventurers. Read on only if you have the mettle for it! What better way to kick off the series than with the greatest of the Great Old Ones: Cthulhu!

Cthulhu is the source of anxiety for all mankind and lays dreaming in the underwater city of R’lyeh, waiting to rise once more and lay ruin to creation. I am not personally a huge Lovecraftian fan (Cthulhu Saves the World aside, give me some Poe any day) and to put this build together I worked backwards from Paizo’s statblock for Cthulhu in Pathfinder Roleplaying Game: Bestiary 4. The golems are comprehensive designers that do great work and I’m positive their research would far outweigh mine so I’m making good on that resource.

Gargantuan aberration (great old one), chaotic evil

Armor Class
24 (natural armor)
Hit Points 585 (30d20+270)
Speed 60 ft., fly 200 ft., swim 60 ft.

27 (+8)​
19 (+4)​
28 (+9)​
28 (+9)​
30 (+10)​
27 (+8)​

Skills Arcana +18, History +18, Insight +19, Intimidation +17, Investigation +18, Nature +18, Perception +19, Religion +18

Damage Resistances
acid, fire, lightning, necrotic, thunder; bludgeoning, piercing, and slashing from magical or adamantine weapons

Damage Immunities
cold; bludgeoning, piercing, and slashing from nonmagical weapons not made from adamantine

Condition Immunities
charmed, diseased, frightened, paralyzed, petrified

darkvision 200 ft., truesight, passive Perception 29

Deep Speech; telepathy 300 ft.

30 (155,000 XP)

Immortality. If Cthulhu is killed, its body immediately fades away into a noxious cloud of otherworldly vapor that fills an area out to its reach. This cloud blocks vision as fog cloud, but can't be dispersed by any amount of wind. Any creature in this area must succeed at a DC 27 Constitution saving throw or be poisoned for as long as it remains in the cloud and for an additional 1d10 rounds after it leaves the area. Cthulhu returns to life after 2d6 rounds, manifesting from the cloud and restored to life via resurrection, but has 5 levels of exhaustion and cannot take both a move and action in the same turn. At the end of each of its turns, Cthulhu makes a DC 20 Constitution saving throw to reduce its exhaustion level by 1. If slain again while suffering from this effect, Cthulhu reverts to vapor form again and its essence fades away after 2d6 rounds, returning to its tomb in R'lyeh until it is released again.

Innate Spellcasting. Cthulhu’s innate spellcasting ability is Wisdom (spell save DC 27; spell attack +19). It can innately cast the following spells, requiring no material components:
Constant: freedom of movement, true seeing
At will: astral projection, control weather, dispel magic, dream, phantasmal killer, sending, suggestion, teleport
3/day: antipathy, feeblemind, gate, plane shift, weird
1/day: power word stun, symbol, wish

Insanity. Any creature that attempts to interact directly with Cthulhu's thoughts (such as via detect thoughts or telepathy) must succeed at DC 27 Wisdom saving throw or gain an indefinite madness. When using its telepathy to communicate Cthuhlu doesn't activate this feature unless it spends an action to focus its mind on one opponent.

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

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

Nightmare Haunting. While on the Ethereal Plane or Material Plane, Cthulhu magically touches a sleeping humanoid on the Material Plane. A protection from evil and good spell cast on the target prevents this contact, as does a magic circle. As long as the contact persists, the target has dreadful visions. If these visions last for at least 1 minute, the target gains no benefit from its rest, and its hit point maximum is reduced by 7 (2d6). If this effect reduces the target's hit point maximum to 0, the target dies and its soul travels to R'lyeh. The reduction to the target's hit point maximum lasts until removed by the greater restoration spell or similar magic. For every 5 minutes the visions last, the target gains a short-term madness. For every 10 minutes the visions last, the target gains a long-term madness.

Non-Euclidean. Cthulhu does not exist wholly in the physical world, and space and time strain against its presence. Its apparent and actual position are never quite the same, and creatures have disadvantage on attack rolls against it. A creature with truesight does not have disadvantage but a DC 17 Wisdom saving throw is needed each time it looks at Cthulhu. On a failure, the creature gains a short-term madness. On a failure by 5 or more, the target also gains a long-term madness.

Regeneration. Cthulhu regains 30 hit points at the start of its turn if it has at least 1 hit point. Cthulhu dies only if it starts its turn with 0 hit points.

Starflight. Cthulhu can survive in the void of outer space and flies through the cosmos at incredible speeds. The exact travel time varies from one trip to the next, but a trip within a solar system normally takes Cthulhu 2d6 hours, and a trip beyond normally takes 2d6 days (or more, at the GM's discretion).

Summon Alien. Cthulhu can use a bonus action to conjure any aberration of CR 12 or lower. The creature appears in an unoccupied space that Cthulhu can see within 100 feet. This feature otherwise functions as conjure elemental but does not require Cthulhu’s concentration.


Multiattack. Cthulhu can use its Mind-Shattering Presence. It then makes six attacks: two with its claws and four with its tentacles.

Claws. Melee Weapon Attack: +17 to hit, reach 40 ft., all targets in a 10-foot square (any creature in the area whose AC is equal to or less than the result is hit). Hit: 26 (4d8+8) slashing damage plus the target is grappled (escape DC 25).

Tentacles. Melee Weapon Attack: +17 to hit, reach 30 ft., one target. Hit: 26 (4d8+8) bludgeoning damage plus the target is grappled (escape DC 25). A target that takes 20 or more damage makes a DC 27 Wisdom saving throw or gains a short-term madness. On a failure by 10 or more, the target gains a long-term madness instead.

Mind-Shattering Presence. Each creature of Cthulhu's choice within 300 feet of it and aware of it must succeed on a DC 17 Wisdom saving throw or die from terror. A creature immune to fear that fails its saving throw is stunned 1d4 rounds instead of killed. On a success, a creature is immune to Cthulhu’s Mind-Shattering presence for 1 minute.

Swallow. Cthulu makes one tentacle attack against a Medium or smaller creature it is grappling. If the attack hits, that creature takes the tentacle’s damage and is swallowed, and the grapple ends. While swallowed, the creature is blinded and restrained, it has total cover against attacks and other effects outside Cthulhu. At the start of each of Cthulhu’s turns the swallowed creature takes 42 (12d6) necrotic damage and makes a DC 27 Wisdom saving throw. On a failure, the creature gains one short-term madness. On a failure by 5 or more, the creature also gains a long-term madness, and on a failure by 10 or more the creature gains an indefinite madness as well.
If Cthulhu takes 30 damage or more on a single turn from a creature inside it, Cthulhu must succeed on a DC 15 Constitution saving throw at the end of that turn or regurgitate all swallowed creatures, which fall prone in a space within 10 feet of Cthulhu. If Cthulhu dies, a swallowed creature is no longer restrained by it and can escape from the corpse using 15 feet of movement, exiting prone.

Design Notes: Obviously for 5E we need something less complicated than a top level Pathfinder monster—it’s a different game system with different goals. That said this is a top level 5E monster so it’s still packing a wallop. Lair actions seemed extraneous and while my Lovecraft-fu is weak, I get the impression that killing Cthulhu while in R’lyeh is intended to be impossible so taking those out of the mix sort of displaces that eventuality anyway. On one hand it’s a little bit easier to hit and less beefy than a tarrasque, but on the other hand Cthulhu just straight up kills creatures that can’t handle its Mind-Shattering Presence, and even if the party has a paladin handy they are still in for some unpleasantness on a failed save. Speaking of saves some of the astute readers have probably already picked out a few weaker save DCs that are bereft of an ability modifier in the equation; this is to make the monster survivable and something that might judiciously be used at someone’s table for either a really, really epic fight or a descent into TPK madness.

Thanks for checking out the new column and stay tuned for more Great Old ones! :D
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Mike Myler

Mike Myler


5ever, or until 2024
Oh I like that. More please! Could probably do a little more with the craziness, but its good start for this column.


Nice start to the series. A little weak for my tastes, but I imagine you will be keeping things at CR 30 or below for this series so I get it.

However, given that its reach is 40' and it is intended to be beyond the scope of a typical gargantuan creature, I have at least two suggestions:

1) Str 30. It is bigger than anything else described by WotC, it probably at least needs a strength score to justitfy that.

2) Given that it is so big, I would give it a trait to describe its size and the effects of that size. This may come in handy for other epic monsters as well. I typically do something like this:

Colossal. Cthulhu's space is 50 feet by 50 feet, it stands 80 feet tall, and it has advantage on Strength (Athletics) checks versus Huge or smaller creatures. In addition, any Large or smaller creature can enter its space and must do so to hit Cthulhu with melee attacks with a reach of 10 feet or less. Additionally, when Cthulhu hits a Medium or smaller creature with a melee attack, each creature adjacent to the primary target must make DC 26 Dexterity saving throw or take equal damage.

Kobold Boots

Clarification request:
If Cthulhu takes 30 damage or more on a single turn from a creature inside it.

Want to be sure the intention is 30 damage or more from a single creature on a single turn?


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