Great Old One

The Great Old Ones, sometimes known as the Elder Gods or simply the Old Ones, were beings that existed before the universe, according to the Seventh Doctor. (PROSE: White Darkness, All-Consuming Fire, Millennial Rites) More a pantheon than a species, the Old Ones included the Toymakers, the Guardians of Time, and even "Greater Old Ones," the Grace.

Overview
The Great Old Ones were unimaginably ancient creatures that were preserved in humanity's race memory as their worst nightmares. They were conceived as creatures that spread evil, chaos and destruction wherever they went. (AUDIO: The Roof of the World) They were known to be one of a number of creatures that had adapted in a way that made them capable of perceiving the higher dimensions. (PROSE: Tomb of Valdemar)

Quantum mnemonics was known to be the language of the Old Ones, as they represented physical laws of the Universe that preceded the current one. It was considered the Old Ones' equivalent of Block Transfer Computations and allowed them to rewrite reality on the most fundamental of levels. (PROSE: Millennial Rites) It was known that the Great Old Ones were incapable of being killed in the normal dimension. They also knew of the Time Lords and considered them a threat. (PROSE: White Darkness)

Biology and power
The Old Ones originally possessed physical bodies in their own universe. Upon entering N-Space, they received new bodies that may or may not have had heads (PROSE: Millennial Rites) and some lost theirs when they ran from the Fendahl, abandoning their forms and letting their minds drift into the Time Vortex. (PROSE: White Darkness) Afterwards they could assume a form for a brief period but not forever, their new natural state being a collective consciousness, possessing neither form nor substance. They existed between dimensions where they created universes, planes, and whatever else suited them,(PROSE: Divided Loyalties) including the Land of Fiction(PROSE: Conundrum) and the Celestial Toyroom, which the Toymaker created and resided in, able to step outside but never fully leave. (AUDIO: The Magic Mousetrap)

They sought to return to their bodies and had a third part of their form which existed in the outer dimensional planes which some believed was where they originated from. They could not be killed in the normal dimension,(PROSE: White Darkness) the Toymaker explaining that were he to die he would simply reappear. (AUDIO: Solitaire) The sensors of a TARDIS noted the body of an Old One appeared as a massive quantity of energy which was the equivalent of twenty billion nuclear bombs. (PROSE: Millennial Rites)

While they were considered an actual race, (PROSE: Twilight of the Gods) their biology differed between individuals. The Celestial Toymaker carried his own mass with him, projected from his original universe. (AUDIO: The Nightmare Fair) He and the Gods of Ragnarok maintained humanoid appearances, as did the Guardians, although Rassilon theorised that they took on familiar forms to whoever they appeared before. (PROSE: Divided Loyalties) The Animus, Intelligence, and Fenric were noted for having multi-limbed bodies, a form the Nestenes generally took; although an Old One, the Nestenes were their own race, albeit a "singular entity" because of their hive mind. Similarly, the Karnas'koi, Gods of Ragnarok, Archons, and possibly even the Lloigor, seemed to be their own sub-species.

The powers of the Old Ones varied between individuals, but included:


 * time travel or following someone in time (TV: The Web of Fear, The Curse of Fenric, PROSE: The Well-Mannered War)
 * existing in multiple time zones (TV: The Greatest Show in the Galaxy)
 * possession (TV: The Abominable Snowmen, The Web of Fear, The Curse of Fenric)
 * creating thunder and lightning (TV: The Greatest Show in the Galaxy, The Curse of Fenric)
 * re-animating dead bodies (TV: The Greatest Show in the Galaxy)
 * generating fog/fungus and webbing (TV: The Web Planet, The Web of Fear)
 * stopping a TARDIS in flight (TV: The Web of Fear)
 * extending an individual's life (TV: The Abominable Snowmen, PROSE: White Darkness, AUDIO: The Nightmare Fair)
 * manipulating and relocating timelines (AUDIO: Protect and Survive)

Other powers were demonstrated seemingly exclusively by the Guardians of Time and the Toymakers.

Society
Before arriving in N-Space, the Old Ones were thought to be the equivalent of Time Lords in their universe, though it is unknown if they performed the same duties. (PROSE: Millennial Rites) While many Old Ones were imprisoned or located elsewhere, the others occasionally came together, usually to watch other Old Ones play games on the Board. Despite their great power, they needed the lesser creatures of the universe to give them perspective in spite of their hatred for them. To them the games were all that mattered to make existence worthwhile. Among themsleves, it was general consensus that Fenric was too dangerous even by their standards. (AUDIO: Gods and Monsters)

Despite also playing games, some of the Elder Gods thought of the Eternals as leading pathetic existences. Within the Old One pantheon were the Guardians (PROSE: Divided Loyalties), the Grace (AUDIO: The Chaos Pool), the Toymakers, and reference has been made to the survivors of the pre-universe, including "a handful of baby godlings and great intelligences." (PROSE: Christmas on a Rational Planet)

History
According to the Time Lords, the beings that became known as the Old Ones did not originate from this universe, but the one before it. They were originally a powerful race of beings who were the equivalent of the Time Lords in their native space. However, when their Universe ended, the Old Ones shunted themselves into a parallel dimension which collapsed seconds later into the new Universe. This allowed them to pass into the new Universe which had different laws of physics, and they discovered that they had gained god-like powers which allowed them to manipulate the new Universe in which they now existed. (PROSE: Millennial Rites)

However, the Carnival Queen maintained that the Great Old Ones were not from a previous universe, but from an early period in this universe, before the Time Lords imposed reason and order upon it. (PROSE: Christmas on a Rational Planet)

The Great Old Ones were known throughout the universe as terrible creatures that sought to destroy others or incorporate them into their being. (PROSE: Twilight of the Gods) They were worshipped as gods on Earth during the age of the Silurians, and by an even earlier set of gargantuan entities that once ruled the planet; they were also known to a cult of the Shobogans. According to the legends, it was believed that Azathoth was the weakest of their kind. (PROSE: All-Consuming Fire)

Ancient carvings dating at least fifteen million years ago show that the Old Ones ruled everywhere before they died out and went into hibernation after fleeing from the predators with a touch of decay. They managed to escape from the great cosmic disaster in order to flee into the Time Vortex There they became discorporate entities, thus leaving their bodies behind on Earth.

Their minds sought to return to their bodies when the stars were correctly aligned with the tidal forces of the stellar masses, an event which can bring about a sufficient tear in the space-time continuum to create a pathway back to their bodies. However, as the stars were constantly expanding and contracting, they never returned to the same configuration as the time when the Old Ones went into hibernation. Thus, they required the assistance of their followers to attract the attentions of their bodies; autonomic instincts and allow them a chance to compensate. As they were unable to affect the world physically, they used the influence of their powerful minds to achieve their goals. (PROSE: White Darkness)

At one point they attempted to enter into the higher dimensions by using the Palace of the Old Ones to power a gateway. One of their number, known as Valdemar, discovered that his kind were unprepared for the perceptions of this new reality and were being driven mad by it. This breach would have destroyed the universe had Valdemar not sacrificed himself to seal the breach. Legends would spread across the galaxy that he was a dark god that nearly destroyed the Old Ones though the truth was far different. The mystery of Valdemar and the Old Ones was later known as the sixth of the great mysteries of the universe. (PROSE: Tomb of Valdemar)

The Pharaoh Amenhotep II discovered them at one time on Earth and attempted to harness their power for himself. However, he came to realise that they were beyond his control and lured them into a white pyramid with a structure of infinite reflections where the creature's evil was to be trapped forever. This trap succeeded and kept the world safe from their evil. (AUDIO: The Roof of the World)

List of Great Old Ones

 * Azathoth Great_Old_Ones.jpg, Magog, Yog-Sothoth, Nah, Raag, Rok (Gods of Ragnarok) and the Animus.]]
 * Cthulhu
 * Dagon
 * Hastur the Unspeakable
 * Several Lloigor, including the Animus
 * Nyarlathotep
 * Shub-Niggurath
 * Yog-Sothoth, later known as the Great Intelligence.
 * Gog
 * Magog
 * Raag
 * Nah
 * Rok
 * Valdemar
 * Kwundaar
 * The Karnas'koi including CP Doveday
 * The Mi'en Kalarash
 * Traguam
 * Kai'lizakia
 * Derleth
 * Moloch
 * Two unnamed Elder Gods disguised as Albert and Peggy Marsden
 * Weyland
 * Nestene Consciousness
 * The Archons
 * White Guardian
 * Black Guardian
 * Red Guardian
 * Gold Guardian
 * Azure Guardian
 * The Celestial Toymaker
 * Hecuba

In addition, Tor-Gasukk and Malefescent were named by Rassilon but little remains known about them. (PROSE: Divided Loyalties) An Old One was said to be within the Infinite as a power source. (TV: The Infinite Quest)

Behind the scenes

 * The Great Old Ones originated out of the, a based on the writing of H. P. Lovecraft and to an extent, some of his contemporaries with which he had corresponded or made extensive revisions for. A few characters and concepts in televised Doctor Who, such as Sutekh (though partly based on an actual ancient Egyptian god, known more commonly as Seth) and the Fendahl, show the influence of the Mythos, and the latter has similarities with Brian Lumley's Chthonians. Not until the novels White Darkness, All-Consuming Fire and Millennial Rites did beings explicitly referred to as Great Old Ones appear in fiction set in the Doctor Who universe.
 * The latter two books took known Doctor Who enemies, such as the Animus, and retconned them into having links to the Mythos. The Taking of Planet 5 revealed that the Elder Things also existed in the form of fiction in the Doctor Who Universe. Though the established Cthulhu Mythos and the Doctor Who version have some differences, stories set in the Mythos frequently contradict themselves.