That is not dead which can eternal lie,
And with strange aeons even death may die…
Here, shall you know the terrors of the void, the nightmare bringers, and the unspeakable lurkers.
Ancient secrets, whispered lore, and collected facts concerning the alien and otherworldly horrors of the Cthulhu Mythos. A cavalcade of monsters and god-like alien intelligences beyond human understanding, all vividly detailed and portrayed. With over 250 entries to inspire countless adventures.
Chaosium Unveiled: Inside The Malleus Monstrorum Bestiary
Watch the unveiling video to see the book for yourself. Remember that you get the PDF when getting the physical copy.
The information within is designed to bring the creatures and bizarre races of the Cthulhu Mythos to life at the gaming table, as well as all manner of Great Old Ones, Outer Gods, Elder Gods, Avatars, and Unique Beings. Their lore and statistics updated and revised for the Call of Cthulhu 7th edition game (and Pulp Cthulhu). All brought to startling life by the illustrations of expert artist Loïc Muzy.
This two-volume collection is packed with ideas, concepts, and insights to immerse your scenarios and campaigns deep in the heart of the Cthulhu Mythos.

Volume 1: Monsters of the Mythos
From the spawn of Abhoth to yuggs, the monsters of the Mythos are herein described, their lore and statistics updated and revised for the Call of Cthulhu 7th edition game.
With over 150 entries concerning Cthulhu Mythos monsters and alien species, as well as creatures from folklore and animal beasts, this tome supplies a wealth of ideas to bring your campaigns and scenarios life with untold horrors.


Volume 2: Deities of the Mythos
Fundamental truths of the cosmos herein lie, to be used to support and inspire countless adventures by bringing Cthulhu, Hastur, Azathoth, and many others to your games. With over 110 entries concerning Great Old Ones, Outer Gods, Elder Gods, Avatars, and Unique Beings, this tome supplies a plethora of ideas to immerse your campaigns and scenarios deep in the heart of Cthulhu Mythos lore.
While humanity may crave both comfort and truth, only one or the other is possible.

Enhance Your Experience

Sold separately, the Malleus Monstrorum Keeper Deck provides over 60 monsters on handy tarot-sized cards for quick reference. After studying and selecting the fiendish mythos beast you plan to throw at your players, keep your epic 2 volume slipcase in your library and come to the table with gorgeously illustrated cards with all relevant information at your fingertips!
Learn more about the Malleus Monstrorum Keeper Deck here.
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What The Critics Say
- Publisher:
- Chaosium
- Rule Set:
- Call of Cthulhu 7th Edition
- Year Released:
- 2020
- Format:
- Full Color PDF (2 volumes)
- Page Count:
- 216 and 264
- ISBN:
- 978-1-56882-334-8
- Authors:
- Mike Mason, Scott David Aniolowski, Paul Fricker
- Cover Artist:
- Loïc Muzy
- Interior Artist:
- Loïc Muzy
- Layout:
- Nicholas Nacario
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Almost Perfect
Absolutely stunning amount of information. This is really an amazing addition to my Call of Cthulhu library. However, there is a saddening lack of illustrations. I was hoping that since it was so "Definitive" that it would have images of every monster. Too many pages are all text.
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A nice improvement!
The books are well writen I like the guidelines on making new monsters or gods. It does seem to be lacking in artwork, not that the art work is bad, it just lacks art work. I also miss that they did not write the name of the author or book each quote comes from in the opening descriptions. It was nice to be able to read that quote and then look up the author and the book to see how the monster was in the original story.
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Malleus Monstrorum
EverythingChaosium has put out for 7th edition has been simply amazing. I have a copy of the 2006 Malleous Monstrorum and this is a drastic improvement. I cannot wait for the slip case hardbacks!
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5/5 Design and Monster Rules, But Lack of Many Illustrations
As said in the subject, the design of the books follows the good guidelines of the 7th. But what is really striking (no need of Spot Hidden for it) is the lack of many illustrations (like Shantaks, Serpent People, Servitor of the Outer Gods, Lloigors!! etc...) I know there some are illustrations in the core book, but for a double one that regroup all the Mythos entities, to have at least one mid sized illustration would not be a luxury... The rest is 5/5, but one star less for it.
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Good but not perfect
Very good book with a lot of content. The cover is exceptionally beautiful. However, I regret a little the lack of illustration for each creature. Still, I'm looking forward to acquiring the physical version.