Great Old One

The Great Old Ones, or Old Ones, are a collection of primordial entities, worshiped as gods by various cults and species across time and space. Their origins are extraterrestrial and possibly extracosmic, their size generally gargantuan, and their powers incomprehensible enough to be often identified as magical. Their fantastic age, eldritch nature and psychic abilities tend to evoke a state of overwhelming fear and horror in the Human mind, which can result in psychological trauma, permanent insanity and even death for those who are unfortunate enough to be in their presence.

Great Old Ones such as Cthulhu and Tsathoggua have been present on Earth since prehistory (in Cthulhu's case since the Paleozoic Era), although they were born far away from the Sol System, spawned by even older entities known as the Outer Gods. Other Great Old Ones can be similarly found inhabiting other planets, as well as other dimensions and realms.

It's unknown whether the Great Old Ones can be considered a species in the biological sense or should be best regarded as a faction, or even a pantheon.

Definition
Although some information about them can be found in occult tomes and prehistoric manuscripts, little is known for certain about the nature of the beings referred to as the Great Old Ones. All that's known is that they are extraterrestrial, fantastically ancient, and their bodies are not made of conventional matter. They are often gigantic and capable of extraordinary abilities. Whether or not they are a species in the biological sense is not known.

Complicating the matter is the fact that the terms "Great Old Ones" and "Old Ones" have also been used to refer to several unrelated species. Cthulhu cultists have been known to use the terms "Great Old Ones", "Old Ones" and "Great Ones" to refer to the Spawn of Cthulhu lying dormant in submerged R'lyeh with their master. William Dyer's account of his ill-fated Antarctic expedition uses "Great Old Ones" and "Old Ones" to refer to the Elder Things, identified by Dyer as the same "Great Old Ones" described in the Necronomicon. In modern usage, however, these species are not considered Great Old Ones. Neither are other unrelated races that are also known as the "Old Ones", such as the K'n-yanians.

In the dreaded Necronomicon, by Abdul Alhazred, it is claimed that the Earth was once inhabited by the "Old Ones", which exist "not in the spaces we know, but between them". This passage further describes them as invisible to man, shapeless and "undimensional", although they do emanate a kind of smell, which is the only aspect of them that can be perceived by Humans under normal conditions. Despite all that, they can somehow interbreed with Humans and their offspring range in form from completely Human-like to monstrously amorphous. However, it should be noted that the passage's emphasis on Yog-Sothoth and Shub-Niggurath and identification of Cthulhu as "Their cousin" (as opposed to one of them) strongly suggests that these "Old Ones" described in the Necronomicon are more likely to be identified as the Outer Gods.

Biology
The physical form and appearance of the entities identified as Great Old Ones is incredibly variable, and almost nothing is known about their biological makeup. For instance, laboratory analysis has revealed that Glaaki's cellular structure is based on a living type of metal, unlike anything known on Earth. Yet some Great Old Ones have been associated with worldly elements, such as Ithaqua, who is an air elemental. While their origins are not clear, it is known that the Great Old Ones are incredibly ancient. For example, the Dweller in the Gulf is believed to be as old as Mars itself.

In some cases, familial relationships between Great Old Ones have been documented. Cthulhu is the father of Ghatanothoa, Ythogtha and Zoth-Ommog. Hziulquoigmnzhah is the paternal uncle of Tsathoggua.

Contrasting with the Outer Gods' frequently abstract and amorphous shapes, many Great Old Ones have an appearance similar to an animal, or a combination of animals. Bokrug, for instance, appears like a huge water lizard, while Atlach-Nacha resembles a giant spider. Cthulhu's appearance combines traits of a dragon, a humanoid and an octopus, whereas Tsathoggua's preferred form has been likened to a toad, a sloth and a bat (though as a shapeshifter, he can assume other forms as well). Additionally, some Great Old Ones are deeply associated with a specific kind of animal, to the point of protecting and/or controlling these animals. Yig is regarded as the father of snakes and is extremely protective of them. Gloon is associated with, and possibly commands, dolphins.

In other cases, Great Old Ones seem to be closely associated with a sapient species which may or may not physically resemble them. In cases like this, the species will worship the Great Old One, and the Great Old One might even protect and guide them. Examples of such associations include: Alala and the S'glhuoans, Bokrug and the Thuum'ha, Cthulhu and the Spawn of Cthulhu, Dagon and the Deep Ones (although Dagon's status as a Great Old One is debatable), etc. It is also possible for Great Old Ones to be associated with locations and objects, and even something as abstract as the text of a book, as in Hastur's association with the cursed play known as The King in Yellow.

The existence of the Spawn of Cthulhu suggests that Great Old Ones can spawn lesser species, just like they themselves are believed to have been spawned by the Outer Gods. Some, such as Glaaki and Atlach-Nacha, have means to physically transform Humans into inhuman servants.

Although they are not made of conventional matter, Great Old Ones can feed on Humans, for instance, Chaugnar Faugn and Rhan-Tegoth feed on Human blood in great quantity. Eihort goes as far as to use living Humans as hosts to incubate its brood.

Great Old Ones have displayed a number of extraordinary abilities, such as manifesting themselves in dreams and regenerating from damage. Quachil Uttaus dwells "beyond the outermost circle, in the dark limbo of the unsphered time and space", has control over time itself and causes any material it touches to age and crumble to dust. Rlim Shaikorth can exert control over its surroundings to create unbearable cold and alter the physiology of select Humans (albeit only wizards) to be able to tolerate such temperature. It can also move enormous objects by sheer willpower, influence and absorb minds. When a Great Old One is angered, the results are usually catastrophic, as demonstrated for instance by Bokrug's complete annihilation of the city of Sarnath.

In many cases, the mere presence of a Great Old One is enough to drive a Human being to despair and madness. Cthulhu, Dagon and Rhan-Tegoth have been known to have this effect, as does the mysterious idol of Gloon. The Martian Dweller in the Gulf exerts influence over the minds of other creatures and projects mental images. Like Cthulhu, Glaaki can project its image into the minds of dreamers, although it only seems to affect those in a very close radius, whereas Cthulhu's influence is felt worldwide when he awakens. Conversely, Tsathoggua and his uncle Hziulquoigmnzhah have both demonstrated the capacity to converse casually with Humans without having any effect in the Human's mental state and sanity.

In spite of their great power, it is possible for Great Old Ones to be damaged by conventional means. Cthulhu was damaged by a ramming boat, Rlim Shaikorth was killed by a sword, and it's possible that Byatis was killed by incineration. Without sacrificial victims, it appears some Great Old Ones become so weak as to enter a dormant state (Rhan-Tegoth) or become imprisoned within simple walls without being able to escape (Byatis). In other cases, however, it takes an extraordinary amount of power to damage them. Even a weapon as destructive as Roger Little's anti-entropy ray required several minutes of continuous exposure to become effective against Chaugnar Faugn, and even then it only managed to banish the god back to its cosmic birthplace, not destroy it.

The Great Old Ones' ability to travel to other worlds is variable. For instance, it is known for a fact that Vulthoom couldn't travel from Mars to Earth without a spaceship.

At least some Great Old Ones are vulnerable to certain star-signs, and can be defeated by the energy weapons carried by the Star-Warriors.

List of Great Old Ones

 * Abholos
 * Alala
 * Ammutseba
 * Amon-Gorloth
 * Animus
 * Aphoom-Zhah
 * Archon
 * Arwassa
 * Atlach-Nacha
 * Ayi'ig
 * Aylith
 * B'gnu-Thun
 * Baoht Z'uqqa-mogg
 * Basatan
 * Bokrug
 * Bugg-Shash
 * Byatis
 * Celestial Toymaker
 * Chaugnar Faugn
 * Coatlicue
 * Coinchenn
 * Crom Cruach
 * Cthaat
 * Cthaeghya
 * Cthugha
 * Cthulhu
 * Cthylla
 * Ctoggha
 * Cyäegha
 * Cynothoglys
 * Derleth
 * Dhumin
 * Dweller in the Gulf
 * Dygra
 * Dythalla
 * Dzéwà
 * Eihort
 * Eidolon
 * E'ilor
 * Etepsed Egnis
 * Fenric
 * Fthaggua
 * Ghadamon
 * Ghatanothoa
 * Ghisguth
 * Gi-Hoveg
 * Glaaki
 * Gleeth
 * Gloon
 * Gobogeg
 * God of the Red Flux
 * Gods of Ragnarok
 * Gog-Hoor
 * Gol-goroth
 * Golothess
 * The Great Intelligence
 * Grace
 * Green God
 * Gog
 * Groth-Golka
 * Gtuhanai
 * Guardians of Time
 * Gurathnaka
 * Gur'la-ya
 * Gwarloth
 * Gzxtyos
 * Han
 * H'chtelegoth
 * Haiogh-Yai
 * Hastalŷk
 * Hastur
 * Hecuba
 * Hnarqu
 * Hziulquoigmnzhah
 * Idh-yaa
 * Inpesca
 * Iod
 * Istasha
 * Ithaqua
 * Janai'ngo
 * Juk-Shabb
 * Kaalut
 * Kag'Naru of the Air
 * Kai'lizakia
 * Karnas'koi
 * Kassogtha
 * Kaunuzoth
 * Khal-kru
 * Klosmiebhyx
 * K'nar'st
 * Krang
 * Kthaw'keth
 * Kurpannga
 * Kwundaar
 * Lam
 * Lexur'iga-serr'oth
 * Lloigor
 * Lolaius
 * Lythalia
 * Magog
 * Mappo no Ryujin
 * M'basui Gwandu
 * M'Nagalah
 * Mi'en Kalarash
 * Mhar
 * Mnomquah
 * Moloch
 * Mordiggian
 * Mormo
 * Mortllgh
 * Mynoghra
 * Nctohlu
 * Nctosa
 * N'girrth'lu
 * Northot
 * Nssu-Ghahnb
 * Nug
 * Nyaghoggua
 * Nycrama
 * Nyogtha
 * Ob'mbu
 * Oorn
 * Orgesh
 * Othuum
 * Othuyeg
 * Perse
 * Pharol
 * Poseidon
 * Psuchawrl
 * Ptar-Axtlan
 * Quachil Uttaus
 * Quyagen
 * Q'yth-az
 * Raandaii-B'nk
 * Ragnalla
 * Raphanasuan
 * Rhagorthua
 * Rhan-Tegoth
 * Rhogog
 * Rh-Thulla of the Wind
 * Rlim Shaikorth
 * Rokon
 * Saaitii
 * Scathach
 * Sebek
 * Sedmelluq
 * Sfatlicllp
 * Shaklatal
 * Shathak
 * Shaurash-Ho
 * Sheb-Teth
 * Shista
 * Shlithneth
 * Sho-Gath
 * Shterot
 * Shudde M'ell
 * Shuy-Nihl
 * Sthanee
 * S'tya-Yg'Nalle
 * Summanus
 * Swarog
 * Tawil at'Umr
 * Thanaroa
 * Tharapithia
 * Thasaidon
 * Thog
 * Tor-Gasukk
 * To'Koth
 * Toth
 * Toymakers
 * Th'rygh
 * Traguam
 * Tsathoggua
 * Tulushuggua
 * Turua
 * Uitzilcapac
 * Ut'Ulls-Hr'Her
 * Vhuzompha
 * Vibur
 * Vile-Oct
 * Volgna-Gath
 * Voltiyig
 * Volund
 * Vthyarilops
 * Vulthoom
 * Worm that Gnaws in the Night
 * Xalafu
 * Xchtol
 * Xhamen-Dor
 * Xinlurgash
 * Xirdneth
 * Xitalu
 * Xotli
 * Xoxiigghua
 * Y'golonac
 * Yeb
 * Yegg-Ha
 * Yhagni
 * Yhasthur
 * Yig
 * Y'lla
 * Ymnar
 * Yog-Sapha
 * Yorith
 * Ysbaddaden
 * Ythogtha
 * Yug-Siturath
 * Zathog
 * Zhar
 * Zindarak
 * Zoth-Ommog
 * Zstylzhemghi
 * Zu-Cha-Quon
 * Zushakon
 * Z'toggua
 * Zvilpogghua

Cthulhu Armageddon
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Doctor Who
"The racial memory of the entire species has preserved your kind as one of humanity's most basic nightmares. You embody everything from the bogeyman to the four horsemen of the apocalypse."

- The Fifth Doctor, 1917

The Great Old Ones are an immortal species from the Dark Times of the universe. They can use psychic projection to manifest as many different forms, including Human form and a giant cloud of organic matter filled with arms, legs, claws and tails of multiple kinds of extinct creatures. Pharaoh Amenhotep II somehow imprisoned them in a pyramid in the interior of Mt. Everest in the Himalayas.

In the distant past, the Great Old Ones were a powerful species that moved from world to world bringing chaos, insanity and death, being worshiped as gods by several races. The Fifth Doctor has described them as a parasitic species, capable of telepathy and telekinesis. He believes that the Great Old Ones imprisoned in Mt. Everest are the last remnants of a dying race and have interbred with other species in a desperate attempt to survive, resulting in a wide array of mutations.

Marvel Comics
TBA

Pathfinder
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Return of the Old Ones
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Usage and definition

 * Despite being a central element of the Cthulhu Mythos, the Great Old Ones have never been explicitly defined in Lovecraft's writings, meaning that it's not possible to indisputably identify any specific entity as a Great Old One, without resorting to other authors.
 * In "The Call of Cthulhu", the term "Great Old Ones" was actually used to refer to the Spawn of Cthulhu. This is made clear in At the Mountains of Madness, in which the entities imprisoned in R'lyeh along with their high-priest and leader Cthulhu (i.e. the ones which Old Castro referred to as the "Great Old Ones" in the earlier tale) are positively identified as the Spawn of Cthulhu. Confusingly, At the Mountains of Madness itself uses the terms "Great Old Ones" and "Old Ones" to refer to an entirely different species which is more commonly known nowadays as the Elder Things.
 * Elsewhere in Lovecraft's works, the term "Old Ones" has been used to refer to the Outer Gods ("The Dunwich Horror"), the K'n-yanians ("The Mound"), the Mi-Go ("The Whisperer in Darkness") and once again the Elder Things ("The Shadow Out of Time"). "Old Ones" is also used in "The Shadow Over Innsmouth" and "The Horror in the Museum", but what the term refers to isn't clear.
 * Although the entities that are generally referred to as "Great Old Ones" nowadays have never been positively identified as a species, the idea of them being related to each other and descended from the Outer Gods does originate from Lovecraft. "The Dunwich Horror" identifies Cthulhu as a cousin of the "Old Ones", which in this context refers to beings such as Yog-Sothoth and Shub-Niggurath (i.e. the Outer Gods). The notion that they all descend from Azathoth is present in a genealogical chart in a letter that Lovecraft wrote to James F. Morton in 1933. Additionally, while the chart displays the lineages of Cthulhu and Tsathoggua, Clark Ashton Smith had his own ideas about the latter's heritage (although he also listed "Tulu" as a relative). However, these too are not present in his published fiction, save for the fact that Tsathoggua is the nephew of the Saturnian god Hziulquoigmnzhah. And even that is entirely dependent on one's acceptance of the idea that Zhothaqquah and Tsathoggua are one and the same, which is widely accepted, but not explicitly stated.

Imprisonment

 * It is believed that at the moment the Great Old Ones are limited in their freedom of action and movement, like captives. The reason and nature of this "imprisonment" is unclear. There is no direct indication of this in the works of Lovecraft, and other authors offer different interpretations.
 * The most popular version is that the Old Ones were once defeated by another race of supernatural beings, the Elder Gods. Often, the confrontation between the Great Old Ones and Elder Gods is considered as a confrontation between evil and good which is incorrect. The Elder Gods are only conditionally "good" for people, and in fact they are no less alien to people than the Great Old Ones. In a number of works by Lovecraft's followers, heroes use the "Elder Sign" to protect themselves from the Great Old Ones.
 * According to another interpretation, the Great Old Ones disappeared from the visible universe of their own accord, or fell into a state resembling the physiological hibernation of animals.

Other notes

 * Some of the entities that have been identified as Great Old Ones actually predate Lovecraft. For example, Hastur originates from Ambrose Bierce's "Haïta the Shepherd" (1891), and Alala originates from Arthur Machen's "The White People" (1904).
 * Some entities' status as Great Old Ones can be disputed. For example, Dagon and to a lesser extent Hydra are interpreted by some as Great Old Ones, and by others as merely gigantic Deep Ones. Gnoph-keh was apparently intended by Lovecraft as a unique being, but some authors interpret it as a species.