Sandy Petersens Cthulhu Mythos


Sandy Petersen’s Cthulhu Mythos for 5e


Designer: Sandy Petersen, et. al.

Artist: Kent Hamilton,

Publisher: Sandy Petersen Games

Year Published: 2018

No. of Players: 2+

Ages: NA

Playing Time: NA

Main mechanic / Theme: Roleplaying Game 5e / Cthulhu Horror

The Elder Gods are older than time, and larger than the universe.

Find more info on


If you are a horror fan and play role-playing games (RPGs), Sandy Petersen’s Cthulhu Mythos is a game book you need to be look and introduce to your group. I really don’t need to say any more for those familiar with work done by Sandy Petersen. If you are the least bit intrigued with the concept of RPG horror, let me tell you what this is about.

Sandy Petersen’s Cthulhu Mythos (SPCM) is a 400+ page source book created on the open gaming license of the Dungeons and Dragons (DnD) RPG system. It is published by Petersen Games and authored by Sandy Petersen, James Jacobs, Arthur Petersen, Ian Starcher, and David N. Ross. This is a powerhouse combination for RPG and Cthulhu. The years of experience in the combined fields of just the names gives an expectation of something that is going to worthy of having on the game table. I wasn’t disappointed. In a point of personal disclosure, I need to say I am a fan of the writing of H.P. Lovecraft and own a complete collection of his work.

I had the opportunity of getting a PDF version of the book as I was working on a review of Yig Snake Granddaddy Act I: Land out of Time adventure setting of Cthylhu Mythos Sagas for Everything Board Game Not yet published, but I will update a link when it is). A great adventure setting that combines SPCM with the DnD 5e rules. I’m not going to go into the adventure setting except that I like it and focus on SPCM.

You can use SPCM to start a horror campaign world or add a layer to your existing game world with elements of horror. Both ways are covered in the book. I don’t think it would be bad to go with either option.

Gameplay and mechanics


You can add new races designed for the game and take you deeper into the works that created the mythos. For some players this will be something they are looking for, but you don’t need the new races to play in this setting. The races you are playing now will work just as well for creating the mood provided. For each of the races class options are provided to help flesh out the character. There are other class option for your players. Backgrounds and new feats are also provided for bring more depth to the characters.

These are not required if you want to use the material in this book with an existing party or campaign setting. The vast majority of this book isn’t about how to create a game world to stand all by itself, but a world that can be laid on top (or just below) your existing world. This could create that next set of adventures your adventurers may be undertaking as they learn about the plans of the Cult of the Crawling Chaos.

Special Elements

There are some items used in horror that will help build the suspense desired. There are guidelines presented to help in how you run the game and a couple of mechanics: Dread and Insanity. If you have played other Cthulhu based games, you have seen that these play a part in the storytelling. In the stories written and the movies made this is an important element—they don’t call it the Arkham Insane Asylum for nothing.

The mechanic is easy to use and provides great guideline for playing fear, horror, and insanity.

Magic is also addressed. This includes new spells and special mythos spells that can be learned by other classes. As with other aspects of dealing with the Elder Gods there is risk associated with casting these spells and some will embrace the chaos that engulfs them.

You are also given information about specific gear, alien technologies, and text (writing seems to play a pervasive role).

Mythos and Monsters

I am impressed with the adaptation of the mythos into the game. This is where most of the book spends its resources. I am glad they took the time to work out so many details, and that is what I expected.

If you are not familiar with stories of Cthulhu, this provides what you need. Most people today who enjoy a level of horror have had some encounter with a story of the long reaching tentacles from another dimension or the deep reaches of space’s darkness. These are drawn from the setting that Lovecraft and others have built over the years. Here they are interpreted for your use.

The Elder Gods are present along with the cults that worship them. They are presented with their levels of power and their desires. You have an understanding of their plans. They are tied together with the mythos races and the more traditional races of the overarching game. Again, this allows you to intertwine the Cthulhu Mythos into something you are already playing.

But let us not forget the monster that inhabited the pages of earlier stories. They are also present. Here they are given the statistics to allow them to take life on the tabletop. They are ready to defend the ground they have earned as they confront the heroes who hope to push the darkness back.

When you are unsure what needs to be present there are templates and tables to help guide the game master. There are the non-player characters ready for use in building the cult. And, wherever the party of heroes my travel, you can easily identify what is already there.

Theme, Artwork, Illustrations, Graphic Design, and Layout

Four artists combined their talents in this book.

Kent Hamilton provided the cover and Interior art. He has been doing gaming art for a while and his works here show his capabilities. Helge Balzer created the Monster and Great Old One Art for the book. Here they show why they are recognized for their dark fantasy art. Richard Luong provides additional art and Tony Mastrangeli did the graphic design and layout.

Together, this team of artists provides a book that is visually stimulating and meeting the expectations of the mythos. The work is easy to read and information was easy to find.

Final thoughts

I enjoyed going through this tome. The artwork is what a horror fan would expect, and the information of the mythos is ready for use in a game. I enjoyed the adventure that led me to acquire Sandy Petersen’s Cthulhu Mythos. My players know there is more to come from these pages they will be facing. And thankfully (for the players, not the characters) they are looking forward to it.




About the Author

Daniel Yocom does geeky things at night because his day job won't let him. This dates back to the 1960s through games, books, movies, and stranger things better shared in small groups. He's written hundreds of articles about these topics for his own blog, other websites, and magazines after extensive research along with short stories. His research includes attending conventions, sharing on panels and presentations, and road-tripping with his wife. Join him at