From publisher blurb:
“The Most Merciful Thing in the World is the Inability of the Human Mind to Correlate all its Contents.”
H.P. Lovecraft coined the term "Yog-Sothothery" to refer to the fictional myth cycle he invented for his tales -- what subsequently became known as the "Cthulhu Mythos" (after other writers had added their own original horrors to sit beside Lovecraft's).
This book is a resource that seeks to pare away the later inventions and present the purely Lovecraft inventions, compiled with game statistics that make it easy to drop them into roleplaying scenarios, campaigns, and game settings. HPL's many Unnatural Entities, Weird Rituals, Cults, Artifacts, Tomes, and Places in this book can be considered a kind of “grab bag” of elements you can use to infuse any game world with a Lovecraftian flavor.
H.P. Lovecraft's Book of Yog-Sothothery can be considered a comprehensive toolkit for turning any existing setting — whether it is a historical era of our planet, or a fictional world separate from the real world — into a setting suited to the kinds of tales woven by Lovecraft.
Want to run a 1950s spy thriller with a cosmic horror vibe? Simply take a Cold War RPG (for example the Cthulhu Eternal Cold War SRD) and add your preferred selection of entities, cults, rituals, artifacts, tomes and places from this book to support the story you’d like to tell. Want to morph your favorite fantasy RPG into a Lovecraftian fantasy RPG? Pick a bunch of curious monstrosities and gods and add them to the world, adapting cults and artifacts to become the tools of in-world religions conducting unspeakable rites in their name.
The game statistics found in this book are designed to work seamlessly with either the APOCTHULHU RPG or any game in the ever-expanding Cthulhu Eternal family. They can, however, be easily used with other evolved D100 games without any significant re-work, and can augment other percentile-based RPGs (and others) with a little bit of conversion effort.
H.P. Lovecraft's Book of Yog-Sothothery includes game descriptions of 40 Lovecraftian Entities (Gods & Monsters), 21 Unnatural Rituals described by Lovecraft, 8 Bizarre Artifacts, 14 Tomes holding terrible Mythos secrets, 8 sinister Cults with Mythos associations, and 8 Weird Places.
Lovecraft's Entities
Lovecraft populated his short stories and novellas with some truly bizarre gods and monsters ... and now so can you. Each entity has game statistics appropriate to the role they're likely to play in a game (Great Old Ones have just a few numeric stats, but lesser creatures are fully statted).
Azathoth, Beings of Ib, Bholes, Bokrug, Cats of the Dreamlands, Colour Out Of Space, Creeping Corpses, Great Cthulhu, Dagon and Hydra, Deep Ones, Elder Things, Formless Hunter, Ghasts, Ghouls, Gnorri, The God of the Sunken Temple, Great Race of Yith, Gugs, Hastur, Hounds of Death, Hypnos, Keziah Mason, King in Yellow, Leng Folk, Mi-Go, Moon Beasts, Night-gaunts, Nodens, Nyarlathotep, Polyp Horrors, Rat Things, Resurrected Abominations, Resurrected Corpses, Shantaks, Shoggoths, Shub-Niggurath, Spiders From Leng, Star Spawn, Winged Servant, Yog-Sothoth, Zoogs
Lovecraft's Cults
Groups who swear loyalty to the unnatural forces of the universe are rarer in Lovecraft's writings than in many later Mythos authors, but several important cults and cult-like societies are mentioned. No sane human being would wish to be part of such an order, but as adversaries for a chilling scenario, such weird groups can add significant color and menace.
Cannibal Cult of Leng, The Cthulhu Cult, Cult of the Wise Ones, Cult of the Worm, Esoteric Order of Dagon, Shepherds of Hastur (Cult of the Yellow Sign), Starry Wisdom Sect, Witches Covens
Lovecraft's Rituals
Roleplaying games are full of spells and magic, but not like the arcane rituals described in Lovecraft's tales. These are much more subtle and corrosive to the sanity of practitioners, but can offer some rather unique and ... special benefits. Each ritual is described with detailed game mechanics as well as ideas for how they may be used in the context of a scenario.
Accelerated Healing, Aklo Sabaoth, Annihilation, Banish Entity, Body Swap, DHO HNA Formula, Dominate Will, Elder Sign, Elixir of Life, Erase Memories, Essential Saltes, Forge Ancestral Bond, Inflict Harm, Music of the Spheres, Open Dimensional Rift, Powder of Ibn-Ghazi, Prolong Life, See Through The Ages, Sign of Koth, Summon Entities, Voorish Sign
Lovecraft's Tomes
Without a doubt the Necronomicon is one of Lovecraft's most infamous creations, but he also made use of other weird tomes of terror as devices in his stories. Each of his original creations (and real-world tomes he referred to) is described with game statistics outlining the effects -- usually adverse -- that might arise from a detailed study of such an arcane volume.
Azathoth and other Horrors, Book of Azathoth, Book of Dzyan, Brick Cylinders of Kadatheron, CTHULHU CULT (Angell’s Files), Daemonolatreiae Libri III, Ilarnek Papyri, The King in Yellow (play), Liber Damnatus Damnationum, The Nameless Book, The Necronomicon, Pnakotic Manuscripts, The Scientific Notes of Dr. Herbert West, The Seven Cryptical Books of Hsan
Lovecraft's Artifacts
Weird items with peculiar and unnatural powers feature prominently in several of Lovecraft's best known Mythos stories, discoveries which usually lead someone down a rabbit-hole ending in a shocking revelation about the true nature of reality. Such items can be dropped into scenarios as incidental oddities or serve as the centerpoint around which an entire adventure is built. Like rituals, these entries include detailed game statistics to capture the strange effects that are caused by the artifact's operation.
Cthulhu Idol, Golden Tiaras of the Deep Ones, Great Race Mental Projection Apparatus, Jade Soul-Amulet, Mi-Go Brain Cylinder, Mi-Go Communication Implant, The Shining Trapezohedron, The Silver Key
Lovecraft's Places
While many of Lovecraft's stories take place in mundane places, others occur in truly bizarre and Mythos-haunted places in the remote recesses of the world. Such places provide intriging opportunities for different types of adventures -- expeditions into the truly weird and unfamiliar. The depictions included hear sketch out the significance of each site invented by Lovecraft as well as providing some ideas on the practicalities of running a scenario or campaign which involves travel to the locale. These 2 or 3 page summaries are intended to be starting points for extrapolations beyond the hints left by Lovecraft, coupled with some helpful notes on game mechanics that capture the weirdness (and insanity) inherent in each specific place.
Antarctic City of the Elder Things, Carcosa & Lake Hali, Dreamlands of Earth, Irem & The Nameless City, Pnakotus, R'lyeh, Y'ha-nthlei, Yuggoth