Who is Cthulhu?

Cthulhu is a large green being which resembles a human with the head
of a squid, huge bat-wings, and long talons (true, that doesn't really
resemble a human, but bear with me here). According to
H. P. Lovecraft's story "The Call of Cthulhu", Cthulhu rests in a tomb
in the city of R'lyeh, which sank beneath the Pacific Ocean aeons
ago. Cthulhu is dead but not truly dead, as he and his fellow
inhabitants of R'lyeh sleep the aeons away. (Cthulhu is generally
thought of as a "he" for some reason.) From time to time R'lyeh comes
to the surface, and Cthulhu's dreams influence sensitive individuals
across the globe to depict his image, slay, and found cults dedicated
to him. In the past, R'lyeh has sunk after a short time, but the day
will soon come when it rises to the surface permanently and great
Cthulhu strides across a world thrown into chaos and anarchy from his
telepathic sendings.

As has been stated before, Cthulhu is not the most important or
powerful being in the Mythos, but he wins in terms of sheer popularity
among his fans. No one is sure why, but that's the way things are.

What are the "Great Old Ones", "Old Ones", and so forth? How do you
tell them apart?

To begin with, Lovecraft himself did not use the terminology outlined
below. He referred to the "Old Ones" (or "Great Old Ones", "Elder
Ones", "Ancient Ones", and so forth) as applying to different beings
in different stories. For example, Lovecraft used the term "Great Old
Ones" in only two stories: in "The Call of Cthulhu" it referred to
Cthulhu's spawn, and in "At the Mountains of Madness" it was the title
of the starfish-like beings who lived in Antarctica and warred with
the Cthulhu-spawn! The list below covers the standardizations which
have come into use after Lovecraft's death:

       Great Old Ones: Vastly powerful creatures which are the most
       famous creations of the Cthulhu Mythos. Although most of these
       beings differ widely in appearance from each other, some are
       actually 'leaders' or high priests of one species (i.e. Cthulhu
       is a "Great Old One" but he is of a race called, for lack of a
       better name, the "Spawn of Cthulhu"). The individual Great Old
       Ones, however, do not necessarily belong to the same
       species. Various authors have tried to come up with elaborate
       family trees of the Great Old Ones, but for the most part these
       are unconvincing and need not concern anyone but diehard Mythos
       fans.

       One trait of most Great Old Ones is a limitation on their
       influence. Cthulhu is imprisoned beneath the Pacific Ocean in
       the city of R'lyeh, Ithaqua the Wind-Walker is confined to the
       far north of our planet, and so forth. Even those Great Old
       Ones less able to act may reach out and talk in their dreams to
       humans, who learn to revere these beings. The Great Old Ones
       are often worshipped on Earth by insane human cultists and
       other species; Cthulhu himself is served by humans, the
       amphibious deep ones, and his own spawn.

       Elder Gods: A group of beings who oppose the Great Old Ones and
       Outer Gods. The most famous of these is Nodens, Lord of the
       Great Abyss; there are others, such as Brian Lumley's Kthanid
       and Call of Cthulhu's Bast (adopted from Egyptian mythology),
       but none of these have been used in many stories. The Elder
       Gods spring from Derleth's interpretations of the Mythos, and
       many authors refuse to use them, complaining that they turn the
       cosmic indifference of Lovecraft's fiction into a strict
       good-and-evil matchup.  Others consider their inclusion proper
       and fitting within their own interpretation of Lovecraft.

       Great Ones: Also called the "Gods of Earth", these are small,
       weak beings who are worshiped in the Dreamlands. Mortals can
       trick them, but then must answer to the Other Gods which
       protect the Great Ones.

       Other Gods: Beings served by Nyarlathotep who protect the Great
       Ones. They are usually thought to be the same as the Outer
       Gods.

       Ancient Ones: Beings which have escaped their mortal forms and
       now dwell in splendor in their Hall beyond space and time,
       overseen by 'Umr at-Tawil (in "Through the Gates of the Silver
       Key"). The story implies that these might be the Old Ones or
       Great Old Ones, but it is difficult to be sure.

       Old Ones: Either the "Great Old Ones" or the ancient crinoid
       race found in "At the Mountains of Madness" in Antarctica. For
       clarity, Call of Cthulhu refers to the crinoid race as the
       "Elder Things" (another name they are given in Lovecraft's
       story.)

Who are the major Great Old Ones?

Aside from Cthulhu, these are some of the most popular Great Old Ones:

       Cthugha ("The Dweller in Darkness", Derleth): Derleth created
       Cthugha to provide the Mythos with a "fire elemental", and
       never really fleshed it out. It appears as a large ball of
       fire, and is often accompanied by smaller beings called "fire
       vampires" or "flame creatures". Cthugha may only be summoned
       when Fomalhaut is in the sky.

       Dagon("Dagon", Lovecraft/mythology): Dagon was not one of
       Lovecraft's inventions, but a Caananite god of agriculture
       worshiped by the Philistines and whose priests opposed those of
       Yahweh (see 1 Samuel 5:1-6). As a result of an error made by
       the fourth-century scholar St. Jerome and the find of a merman
       depiction near one of his temples, people thought that Dagon
       was a fish-god. Lovecraft himself was not aware of the error,
       and made Dagon the god of the deep ones.

       Glaaki ("The Inhabitant of the Lake", Campbell): A creature
       which dwells beneath a lake near the Severn River. It has a
       slug-like body with stalked eyes and spines, and commands a
       horde of undead servitors.

       Hastur ("Haita the Shepherd", Ambrose Bierce/"The Return of
       Hastur", Derleth): The name "Hastur" first appears in Bierce as
       a friendly god of shepherds. Later, it was adopted by Robert
       W. Chambers as a place-name. When Derleth took it up, he
       changed it into an "air-elemental" who was Cthulhu's
       "half-brother" (whatever that means). See below for more.

       Ithaqua (Mythology/"The Thing that Walked on the Wind",
       Derleth): Derleth needed another "air elemental" for his
       Mythos, so he took a creature from Cree and Ojibwa
       mythology. This creature was the "windigo", a cannibalistic
       giant with a heart of ice. (This legend had previously been
       used in "The Wendigo" by Algernon Blackwood.) Derleth gave this
       being the name "Ithaqua", and included him among the Great Old
       Ones. Even though windigo myths are centered just north of the
       Great Lakes, most Cthulhu Mythos authors insist he is confined
       to the Far North.

       Nyogtha ("The Salem Horror", Henry Kuttner): Also known as the
       Thing that Should Not Be, Nyogtha is a black amorphous mass
       that dwells beneath the ground. He was worshiped by one of the
       witches at Salem.

       Shudde M'ell ("Cement Surroundings", Lumley): A slug-like being
       with tentacles where a face should be. Shudde M'ell spends much
       of its time in Africa, and is the leader of the underground
       species called the cthonians.

       Tsathoggua ("The Seven Geases", Smith): A god resembling a
       furry toad, Tsathoggua dwells in the cavern-world of N'kai.
       Tsathoggua occasionally eats visitors, but is more likely to be
       asleep when encountered.

       Yig ("The Curse of Yig", Lovecraft): This Great Old One appears
       as a huge snake-headed man. He cares little for humanity, but
       brings terrible vengeance on those who attack snakes.

What are some of the major non-human species in the Mythos universe?

Mythos tales refer not only to the Old Ones and their ilk, but also to
less powerful creatures which often have their own agendas. Here are
some of the more common ones:

       Byakhee ("The Festival", Lovecraft -- description; "The House
       on Curwen Street", Derleth, name): Winged creatures which dwell
       in the depths of space near Aldebaran. If a ritual involving a
       magic whistle and a fluid called "space-mead" is performed, a
       byakhee will appear and serve as a mount for the caster. Allied
       with Hastur.

       Deep Ones ("The Shadow over Innsmouth", Lovecraft): Undersea
       dwellers which look like a cross between humans and fish (or
       frogs). Deep ones sometimes breed with humans, creating
       offspring which are human at first but make a slow
       transformation into deep ones. The deep ones serve Dagon and
       Cthulhu.

       Elder Things/Old Ones ("At the Mountains of Madness",
       Lovecraft): Starfish-like entities which are part animal and
       part plant.  They lived on our planet in ancient times, and
       warred with both the mi-go and the spawn of Cthulhu. The Elder
       Things were great scientists, and created humanity as food or a
       joke. They eventually abandoned their Antarctic city to live
       underwater, and it is unknown whether they have become extinct.

       Great Race of Yith/Yithians ("The Shadow out of Time",
       Lovecraft): Time-travelling beings with no true physical form,
       they occupied the bodies of immense iridescent cone-shaped
       creatures millions of years ago. The creatures had long arms
       with pincers, a trumpet-like mouth, and a small round
       head. Members of the Great Race can send their minds into the
       future and swap consciousnesses with dwellers there. They
       usually do so as a part of their research, but at times they
       travel en masse in conquest.

       Hounds of Tindalos ("The Hounds of Tindalos", Long): Creatures
       which dwell in the distant past. They are not a threat unless
       they sense a time-traveller, in which case they hunt the person
       down and kill them. They manifest themselves through angles,
       and cannot enter an area in which all surfaces are curved.

       Mi-go/Fungi from Yuggoth ("The Whisperer in Darkness",
       Lovecraft): Crustacean-like fungoid beings which have an
       outpost on Yuggoth, or Pluto. They come to our world to obtain
       precious minerals and for other dark purposes, though they try
       to remain hidden. They serve Nyarlathotep and Shub-Niggurath at
       times, but often seem independent in their motivations.

       Serpent People ("The Shadow Kingdom", Howard): Millions of
       years ago, the serpent people were mighty sorcerers and
       scientists who ruled vast empires. Today, they hide from humans
       through magic and isolation. Their degenerate descendants were
       the inspiration for the myths of the faeries, or "Little
       People". They do not serve any one god, but seem to favor Yig.

       Shoggoths ("At the Mountains of Madness", Lovecraft): Huge
       protoplasmic beings able to take on any form their masters
       desire.  The shoggoths were created by the Elder Things, but
       rebelled against them, and most of them were destroyed. A few
       may be found in the Elder Things' former cities, or working
       with the deep ones.

       Star-spawn of Cthulhu/Cthulhi ("The Call of Cthulhu",
       Lovecraft(?)): Beings which appear as smaller versions of
       Cthulhu. Most are imprisoned at R'lyeh, but some may still be
       free.