Eldritch Horror RPG

Azathoth — The Blind Idiot God

Often described as an entity of unimaginable power at the center of ultimate chaos, surrounded by grotesque entities making strange music. Azathoth is particularly horrifying because there is essentially no meaningful negotiation with it. It isn't a villain plotting against humanity. Humanity is simply irrelevant. Reality and creation only exist as long as he sleeps.

Yog-Sothoth — The All-in-One

One of the most important entities in the Mythos, Yog-Sothoth is associated with time, space, dimensions, and the barriers between realities. The famous phrase associated with it is: "Yog-Sothoth knows the gate. Yog-Sothoth is the gate." Yog-Sothoth can make seemingly impossible things possible: Doors leading to other eras, people encountering alternate versions of themselves, locations existing in multiple places, time loops, knowledge of events that haven't happened yet, realities bleeding into one another, and more.

Shub-Niggurath — The Black Goat of the Woods with a Thousand Young

Associated with fertility, reproduction, nature, and bizarre monstrous offspring, Shub-Niggurath's imagery tends toward forests, cults, fertility rituals, and grotesque biological abundance.

Nyarlathotep — The Crawling Chaos

Unlike Azathoth or Yog-Sothoth, Nyarlathotep is highly active and enjoys interacting with humans. She is a deceiver, manipulator, prophet, wanderer, and shapeshifter who appears in countless forms. For all intense and purposes, she is omnipresent. She can be anyone anywhere at any place and anytime.

Great Old Ones are usually immensely powerful entities associated with particular locations, planets, cults, or civilizations. They aren't necessarily as cosmically fundamental as the Outer Gods.

Cthulhu

Cthulhu lies dreaming in the sunken city of R'lyeh, waiting for the stars to come into the proper alignment. He's typically described as having an immense humanoid form, an octopus-like head, wings, and claws. But the most important thing about Cthulhu is that his very existence demonstrates how insignificant humanity is. His cultists believe that when the stars are right, Cthulhu will awaken.

Dagon and Mother Hydra

These are associated with the Deep Ones, aquatic humanoids that dwell beneath the sea. Dagon is sometimes treated as a Great Old One and sometimes simply as an immensely powerful deity worshiped by the Deep Ones. The important story from this corner of the Mythos is "The Shadow Over Innsmouth." The Deep Ones are particularly interesting because they're not merely monsters. They can breed with humans. This creates one of Lovecraft's nastiest ideas: the possibility that someone who appears completely human may possess a hidden ancestry connecting them to something ancient beneath the sea.

The Great Race of Yith

The Yith are an ancient species possessing incredibly advanced psychic and scientific technology. Their most bizarre ability is that they can project their minds through time and space, effectively swapping consciousness with another living being. They're responsible for the events of "The Shadow Out of Time." They're fascinating because they aren't inherently evil, they're researchers. They study civilizations across immense spans of time. Unfortunately, their research methods involve stealing your mind, which is somewhat inconvenient.

Mi-Go — The Fungi from Yuggoth

The Mi-Go are an alien race associated with the planet Yuggoth, commonly identified with Pluto. They are bizarre fungal/crustacean-like extraterrestrials capable of extraordinary technology. They're responsible for one of the Mythos's most disturbing concepts: The Mi-Go can essentially transport human consciousness across enormous distances. They're also interesting because they're not necessarily interested in destroying humanity, they have alien goals. Their experiments may be horrifying without them considering themselves evil.

Deep Ones

The Deep Ones are one of the most important races. They are amphibious humanoids living in underwater cities. They're connected strongly with Innsmouth, Dagon, Mother Hydra, cults, interbreeding, and ancient pacts. Their appearance is usually described as vaguely humanoid but distinctly fishlike with bulging eyes, slick skin, gills, fins, claws, and grotesque proportions.

Elder Things

The Elder Things originate primarily in At the Mountains of Madness. They're ancient extraterrestrial beings with bizarre starfish-like bodies and enormous technological capability. They came to Earth long before humanity existed. They created life. They manufactured the primitive organisms that eventually became part of Earth's biological history. They fought enormous wars against other extraterrestrial species and ultimately established civilizations across prehistoric Earth.

Shoggoths

The Elder Things created the Shoggoths as a form of biological slave labor. Shoggoths are essentially enormous masses of constantly shifting protoplasm. They're famous for the horrific cry: "Tekeli-li! Tekeli-li!" Unlike many Mythos creatures, Shoggoths are comparatively physical and visceral. They can be enormous, amorphous, extremely strong, difficult to kill, capable of mimicking forms, and they eventually rebelled against their creators.

Hounds of Tindalos

These creatures are particularly bizarre. They're associated with angles and strange forms of time. They can emerge from corners and other geometrical spaces to hunt people across time.

Nightgaunts

Nightgaunts are strange, silent, winged humanoid creatures associated with the Dreamlands. They have, black skin, leathery wings, tails, no faces, and a tendency to abduct people. They're more mysterious than overtly cosmic.

The Cats of Ulthar

Possibly the most unexpectedly useful faction in the entire Mythos. The cats of Ulthar are intelligent, mysterious, and apparently possess supernatural significance.

Byakhees

The Byakhee is another famous Mythos creature. They are interstellar flying corpse-bird nightmares. They're associated with Hastur and can sometimes be summoned through occult rituals.

Hastur

This one requires a giant asterisk. Hastur predates Lovecraft's Mythos usage and became heavily expanded by later authors. The famous connections between Hastur, The King in Yellow, Carcosa, and the Yellow Sign come largely from Robert W. Chambers and later Mythos writers rather than originating cleanly with Lovecraft.

The K'n-yan

A subterranean civilization. The K'n-yan are an ancient humanlike civilization living beneath North America. Their society possesses technology and psychic abilities vastly beyond contemporary humanity. The horrifying part is that they aren't necessarily monstrous-looking. They're people who have become profoundly alien through unimaginable antiquity.