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.
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 – 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.