Sandy Petersen’s Cthulhu Mythos

The Ultimate Guide to the Cthulhu Mythos in Roleplaying

Sandy Petersen’s Cthulhu Mythos is the most comprehensive guide to including Lovecraftian elements in your Roleplaying game, written by Sandy Petersen, the author of the groundbreaking Call of Cthulhu role-playing game, and developed primarily by James Jacobs and David N. Ross.

This massive tome contains over 100 monster stat blocks, dozens of which are Cthulhu Mythos monsters that have never been described for Dungeons and Dragons 5e or Pathfinder – including new rules for interacting with 25 different Great Old Ones and Outer Gods (they are much more than a simple encounter!).

This is much more than a mere bestiary, however. Inside you will find new rules for Insanity and Dreams; 40 new spells and 30 Rituals – a new magic ruleset; dozens of mythos items and artifacts; dozens of Mythos cults detailed; and four new player races from Lovecraft’s universe – Dreamlands Cats, Mythos Ghouls, Gnorri, and Zoogs – as well as new character options, professions, feats, and race options for them.

Pathfinder 2nd Edition

The Pathfinder 2nd edition is a massive 567 pages!

Sandy Petersen's Cthulhu Mythos for Pathfinder Second Edition

What's In the Book?

  • Everything from the original Pathfinder SPCM in the 2e system
  • Lots of new art, including dozens of illustrations commissioned for this book
  • New Great Old One stats, including: Nodens and the Watcher of the Green Pyramid 
  • New monsters, including the elder thing polymath, gnorri sculptor, gug brute, mi-go thinker, elder shoggoth, and yithian sage
  • Dreamlands cat fighting styles
  • New feats
  • New traps
  • New alien technology and magic items 
  • New spells 
  • The page count is 567


Want a Sample?

How about 38 pages!

5e Fantasy Edition

The 5e Fantasy edition is well over 400 pages long, and available as PDF, hardcover and collectors edition bound in genuine leather. It is not merely a conversion from our Pathfinder edition, but rather a reimagining. It also contains new features, including:

* Over 70 new illustrations not seen in the Pathfinder edition!
* A new avatar of Nyarlathotep, the Dark Demon, as well as more former-human horrors
* Dozens more monsters
* Two new backgrounds (cultist and visionary)
* More Dreamlands denizens
* New character options
* And more!

Download and print the FREE Cthulhu Mythos 5e Fantasy Character Sheets for your game!

Brown Jenkin Pocket 5e Edition

Who is Brown Jenkin anyway? Brown Jenkin appears in Lovecraft’s story Dreams in the Witch House, and it is an extremely unusual entity. It is an old fashioned type of horror – a small rat-like monster with humanoid face and paws. More like the image of a medieval witch’s familiar than a tentacled Lovecraftian thingy! See if you can find him on the cover of this new edition.

Our pocket-sized, softbound version of Sandy Petersen's Cthulhu Mythos for 5e fantasy is printed and shipped, with arrival in our warehouses during the first week of March!

Why did Sandy want to create this version anyway? Watch his recent video to find out!

We've created a special bonus for you as well!

All copies of this new pocket-sized edition will include a bookmark with a stat block for playing Brown Jenkin in your games!

Non-English 5e Editions

Sandy Petersen's Cthulhu Mythos for 5e is now available in German, French, Spanish and Italian. To see more details, please click the links below.

Dark Eye Edition
Now Available!



No Dice Unrolled


...I feel I have a true masterpiece in my hands. Perhaps also because in each of his pages I perceived the same love and passion; and when a job is based on these principles, then it starts off on the right foot. The incredible success achieved by the other versions of this manual is a confirmation...if you like the myths of Cthulhu and PF2, Sandy Petersen’s Cthulhu Mythos is a manual that you cannot miss.

—Andy Lingua


Everything Board Games


The best audience for this adventure is a group that likes to see an ever-expanding story and well-considered lore. Overall, Skin Deep is a memorable adventure that proves to be quite an enjoyable ride.



Beyond The Veil


[In The Big Sleep] There’s plenty of rich political and spiritual drama for a talented DM to weave into the fabric of an exciting escapade, all while anticipating the inevitable appearance of eldritch horrors.

—Benjamin Page, Go Beyond the Veil


Shut Up Nerd Podcast


Dice Chukr - Ep. 01 -- Strangers and Rumors
Join our adventurers; Chad, Jacob, Josh, and Seth as DM Travis takes them through the maddening adventure!

Shut Up Nerd Podcast




"I much enjoyed reading and planning to run Dark Worlds: The Ritual. This is my cup of unearthly tea. "

— Andrew Girdwood,

Read The Review



"...I have rarely received a review item that is so much in my wheelhouse as Ghoul Island. The marriage of the Cthulhu Mythos with my 5E campaign or Pathfinder is like manna from heaven for me. The fact that Sandy Peterson is the person behind this makes it even more appealing."

Read The Review

A Pawn's Perspective


"Ghoul Island offers a fresh, horrifying adventure that will tax even experienced players, pushing their characters to the brink of insanity...and sometimes over the edge."

— Rob Kalajian

Read The Review

Board Game Quest


"As a DM I like the excellent plot hooks and flexible options that Ghoul Island offers...I can't wait to have my DnD group play Ghoul Island""

— Brian Winters

Read The Review



“If you are a fan of horror or interjecting Lovecraftian horrors into your fantasy games, I think that you will really want a copy of Sandy Petersen’s Cthulhu Mythos on your shelves.”

— Christopher Helton

Read The Review

Talking About Games


“This is one of those books that you will read perhaps 20 pages, and you will feel as if only a couple of minutes passed…Everything is very well written and explained…The illustrations are perfect…notes, by Sandy Petersen himself…A very smooth process to learn how you can implement all of this mythos related information into your Pathfinder roleplaying game….Horror into a high fantasy environment….Overall my highest recommendation for Sandy Petersen’s Cthulhu Mythos. You need to get this book!…A bridge between the Call of Cthulhu Roleplaying game…Lovecraft stories, and the pathfinder roleplaying game…The alien beauty of the cthulhy mythos…dark splendour…dread and insanity…”

— Abraham

Watch The Review

Drive Thru RPG


“Put simply, this book is the best Mythos-themed product for Pathfinder. Period. If you want Cthulhu, or anything related to Cthulhu, this is the book to get.”

— James E.

Read The Review



“People who are fans of both Cthulhu and Pathfinder will find a lot to love in Sandy Petersen’s Cthulhu Mythos for Pathfinder. Petersen and his team clearly thought through every aspect of the mythos and how it would change in heroic fantasy like Pathfinder. If you’re interested in bringing horror to your Pathfinder game, Sandy Petersen’s Cthulhu Mythos for Pathfinder is well worth the look. It might become your favorite.”

— Beth Rimmels

Read The Review

Cthulhu Mythos News

Announcing SPCM: Brown Jenkin! September 30, 2021
The Prey June 28, 2021
A Study in Wickedness May 13, 2021
What the Hills Hide April 20, 2021
Diggin’ Deep March 23, 2021
Mini Offer of the Month March 16, 2021
The Turned Tide March 11, 2021
They Dreamed in Yellow February 24, 2021
Mini Offer of the Month February 22, 2021
The House by the Lake February 17, 2021
Not a Xorn January 27, 2021
Mini Offer of the Month January 11, 2021
Mini Offer of the Month December 15, 2020
Meanwhile in Resante… December 13, 2020
The Night is Dark & Young November 20, 2020
Famous Last Words Wanted! November 19, 2020
Night of the Brine November 12, 2020
Mini Offer of the Month November 10, 2020
The Night is Dark & Young October 23, 2020
An Omen in the Stars October 16, 2020
Free Keyless Map Downloads October 13, 2020
Famous Last Words Wanted! October 7, 2020
Mini Offer of the Month October 6, 2020
More Horror with Ghoul Island September 26, 2020
The Pale Shepherd September 17, 2020
Famous Last Words Wanted! September 9, 2020
Ready for Dark Worlds? September 6, 2020
Gaming Practicum Video March 17, 2020
Matt Corley February 26, 2020
Yig Snake Grandaddy February 22, 2020
Yig Snake Grandaddy February 17, 2020
Jonah Bomgaars February 17, 2020
Shout Out to Matt Corley February 5, 2020
More Anatomical Concepts November 10, 2019
More Anatomical Drawings September 19, 2019
Final Opportunity September 9, 2019
Any Anatomy Buffs Out There? September 7, 2019

General Downloads


Dark Worlds Act 4 Keyless Map 3.38 MB 287 downloads

Some folks have asked for the maps in the adventures without the map key to show...

The Ghouls Who Saved Christmas Adventure 2.88 MB 1061 downloads


Dark Worlds Act 3 Keyless Map 3.66 MB 307 downloads

Some folks have asked for the maps in the adventures without the map key to show...

Dark Worlds Act 2 Keyless Map 2.16 MB 308 downloads

Some folks have asked for the maps in the adventures without the map key to show...

Dark Worlds Act 1 Keyless Map 1.41 MB 357 downloads

Some folks have asked for the maps in the adventures without the map key to show...

Yig Snake Granddaddy Gehirs Map 4.45 MB 484 downloads


The Lone Lighthouse 13.21 MB 1457 downloads

Dive into the campaign world with a FREE one-shot adventure* (as PDF) that takes...

5e Sagas Character Sheet 3.09 MB 6610 downloads

Enjoy this FREE character sheets to help keep track of the action. This beautifully...

Ghoul Island Act 4 Keyless Map 2.89 MB 585 downloads

Some folks have asked for the maps in the adventures without the map key to show...

Ghoul Island Act 3 Keyless Map 3.65 MB 596 downloads

Some folks have asked for the maps in the adventures without the map key to show...

Cthulhu Mythos Sagas

Sandy Petersen, the mind that created the horror RPG genre, brings the Cthulhu Mythos to heroic adventure campaigns for 5e. The Cthulhu Mythos Sagas are full campaigns, taking your adventurers from level 1 to level 14 or 15. They are standalone but can easily be introduced into any fantasy setting.

Cthulhu Mythos Saga VI: Skin Deep

NOW AVAILABLE! Skin Deep, a 4 Act Cthulhu Mythos Saga in a single volume!

Fresh Horror Delivered to your doorstep!

In Skin Deep, the heroes defend the lands of humanity against the machinations of extra-dimensional doppelgangers known as sand dwellers. The sand dwellers corrupt susceptible mortals, hollowing out their bodies and stealing their skins to take their places. They have infiltrated human governments and militaries and are undermining them, weakening them against the invasion by their warlord-queen, Ravazel the Butcher.

Can the heroes unravel their schemes and help humanity stand fast against this otherworldly menace, or will they too be hollowed out and replaced?

300 full color pages in hardcover...

...with new monsters to fight...

...and new locations to explore!

stop here

Skin Deep - Now Available

Ghoul Island introduces the Cthulhu Mythos to your heroic fantasy campaign as only the mind that created the horror RPG genre can!  Ghoul Island is a full campaign, taking your adventurers from level 1 to level 14.  It will be published in four volumes, each a separate act.

The first act, Voyage to Farzeen, will take PCs from 1st level to 5th.  It begins with a mutiny and ends in the underground tunnels where our adventurers discover an ancient temple dedicated to a horror thought to have been vanquished long ago!  Ghoul Island can easily be introduced into any 5E fantasy campaign and setting!

Each act is 50+ full color pages in hardcover...

...with new monsters to fight...

...and new locations to explore!

stop here

Ghoul Island - Available Now!

In Yig Snake Granddaddy, the new Cthulhu Mythos for 5e campaign, evil serpent folk seek to bring back prehistoric times, complete with pterodactyls, dinosaurs, and other monstrous beings.

In Land Out of Time, the first act of four, your player characters adventure into the wilds of Yilan, a primeval wilderness infested with carnivorous slime molds, gigantic crocodiles, and other lost horrors. The heroes encounter an evil serpent wizard, who prepares for an evil ritual beyond belief.

Betrayed, marooned, and hunted by super-intelligent enemies, can the heroes even survive, yet alone prevail?

Yig Snake Granddaddy and the Cthulhu Mythos Saga Subscription debuted in May 2020.   Get the full set now with free shipping!

Each act is 75+ full color pages in hardcover...

...with new monsters to fight...

...and new locations to explore!

stop here

Yig Snake Granddaddy - Now Available

Enter the Dark World after the exciting conclusion of Yig Snake Granddaddy!

The next four sagas in your adventure series is NOW AVAILABLE!

In Dark Worlds, the new Cthulhu Mythos for 5e campaign, You and your friends become unwitting pawns caught up in the blunders of a mad ruler. His insane attempt to curry favor with the dread Fungi from Yuggoth results in your being teleported across space to the nightmare world of Yuggoth. The ritual keeps you alive … for now. But how long will its effects last? Your only hope is to track down the wizard Mustafo who was transported along with you, and who knows the spell of return. Unfortunately, Mustafo has been taken by the Fungi for their dire purposes and your attempt to rescue him have drawn their attention …

75+ full color pages in hardcover of Cosmic Horror!

In Act 2: Nithon, you traverse the Radiation Wastes of Yuggoth, encounter creatures and hazards from nightmare as you seek the Forest and City of Nithon. Here lies the Green Pyramid of the Watcher. The Pyramid awakens before your eyes, and you must explore its fearsome depths. Meanwhile, you are in constant threat of being caught up in the battles raging between the Watcher and its spawn versus the Fungi war-cyborgs.

In Act 3: The Zepzeg Cycle, you are brought to Yuggoth’s moon Thog, where you learn of the existence of the Zepzeg – a spacefaring alien species in many ways the antithesis of the Mi-Go. Plus, you learn of a lost colony of gnorri here so far from your world. Can you reconcile the Zepzeg, the Gnorri, and your own goals? Negotiate with an antediluvian entity of enormous psychic power, assist the Gnorri and the Zepzeg to forge alliances to help you in the difficult strife ahead, and find the awesome grimoire detailing a weapon of unthinkable might.

In the fourth and final Act of Dark Worlds, The Green Pyramid, the time has come at last to take the fight to the dread Mi-Go; the Fungi from Yuggoth. Returning to Yuggoth, you find that the Fungi have not been idle in your absence. Can you overcome the Fungi’s might, even with your new allies and eldritch constructs? An epic sacrifice allows ingress to the Pyramid, and you are ultimately led into the Null dimension and confront a being of mindless destruction. The campaign ends by giving you a choice with repercussions that echo across the galaxy. 

stop here

Dark Worlds - Now Available

Enter the Big Sleep after the exciting conclusion of Dark World!

The next four sagas in your adventure series is NOW AVAILABLE!

In Act 1: The Sleeper Rising, you and your fellow heroes are caught between the religious police and a cabal of hidden cultists. Recruited by the king of Axphain, you must begin to root out the cultists. You discover a network of tunnels converging on the Royal Place, which leads to high-stakes intrigue and investigation.

At the King’s masquerade ball, an eldritch horror is unleashed, and the ultimate abomination rises above the city! Yet, this is only the beginning – volume 1 of The Big Sleep – an entire campaign devoted to exploring the terrors and wonders of the Great Old One Tsathoggua – the Sleeper.

75+ full color pages in hardcover of Cosmic Horror!

In Act 2: The Doomed World, you and your allies have temporarily escaped some of the worst effects of Tsathoggua’s rising, but now the Great Old One walks the surface world. What do the Sleeper’s demented cultists seek? You follow a pilgrimage of cultists through a deadly forest, to an enchanted mountain, hollow within. From there you must penetrate and escape a fortress of sub-human bestial horrors.

Eventually your heroes enter the neighboring, not-yet-blighted Kingdom of Yetive. You rush to seek the Queen’s aid, but she has her own plans and goals, and you and your fellow heroes are not the only factions calling upon her.