Great Vampire

The Great Vampires, (TV: State of Decay) also called the djinn in The Thousand and Second Night, (PROSE: Head of State) were a species of huge vampires from another reality. Central to Gallifreyan legend and history, they were accidentally unleashed into N-Space during the Dark Times and fought by the Time Lords in the Eternal War. (TV: State of Decay) Great Vampires were actually emanations and avatars of a demonic force of destruction, which could be understood as a singular conscious entity, known as the Yssgaroth. (PROSE: The Pit, The Book of the War, Preternatural Nights)

Nature
The Yssgaroth could manifest in multiple forms, varying based on what species or individual was perceiving them. These included stems of bloody thorns, tearing flesh from whole worlds; bleeding, eyeless lambs on divine thrones; (PROSE: The Book of the War) huge winged snakes with horns, many eyes, and wet, dripping skin; (PROSE: The Pit) clouds of smoke that would fill a planet's atmosphere and induce nuclear winter; (PROSE: Predating the Predators) and the Great Vampires themselves, "blind, screaming abominations made of leather wings and shredded muscle". (TV: State of Decay, PROSE: The Book of the War, Predating the Predators)

It was often speculated that there was only one Yssgaroth, capable of splitting itself into smaller forms. Some believed that, rather than being alive, the Yssgaroth were areas of hostile anti-structure produced by the collision of the Spiral Politic with another universe, turned into monsters by the Great Houses' and lesser species' projections of their fears. (PROSE: The Book of the War) Erasmus Greatorex interpreted, and communicated with, "the Yssgaroth" as a singular entity, which he described as an Ancient and a demon. (PROSE: The Last Few Pages)

Another view was that the monstrosities were actually members of counterpart Great Houses from that other universe. (PROSE: The Cosmology of the Spiral Politic) The Seventh Doctor went so far as to hypothesise that they and their universe might have been the N-Space Time Lords' own nightmares, rooted in the fear of their own blood, made real by the Time Lords' dwelling on the possibility of their existence. (PROSE: Damaged Goods)

The Vampires needed to steal energy from other sources to survive. Just one was extremely powerful and could drain a whole planet of energy. (TV: State of Decay) With their incredible hypnotic powers, the Vampires could enslave entire planetary populations. (PROSE: Predating the Predators)

They also had extreme regenerative abilities, and they could survive numerous wounds. (PROSE: The Book of the War) Leela's vision was restored after she drank Great Vampire blood. (AUDIO: Annihilation) Because they could absorb energy weapons and heal most wounds, the only way to kill one was to stab them physically through the heart, usually with a steel bolt. More powerful Vampires needed to have their heart fully destroyed in order to kill them. (TV: State of Decay)

Yssgaroth biomass was able to hybridise and corrupt ordinary biomass by contact. This property was called the Yssgaroth "taint" (PROSE: The Book of the War) and was caused by the application of the Yssgaroth observer effect on the Spiral Politic. (PROSE: The Cosmology of the Spiral Politic)

Arrival
Because the story of the Yssgaroth was never recorded in the Matrix, there were varying accounts of their origin; however, whether in one of Rassilon's early experiments creating black holes (PROSE: The Pit, Interference) or during the anchoring of the thread, (PROSE: The Book of the War) all accounts agreed that they were accidentally released from their dimension by the Time Lords. (AUDIO: Project: Twilight) At that instant, one Yssgaroth appeared on the Homeworld, at the site that would later be known as the caldera, as thousands of "servants of the Yssgaroth" began to tear their way into the continuum at many points throughout history. (PROSE: The Book of the War)

Throughout the Dark Times, (TV: The Infinite Quest) the Vampires caused mass destruction and chaos throughout the cosmos. (TV: State of Decay) Through their taint, they created the Mal'akh, (PROSE: The Book of the War) the Saturnyns, (PROSE: The Multi-Faceted War) and Earth's vampires. (PROSE: Vampire Science) The First Doctor also speculated that the Sou(ou)shi were related to the Great Vampires. (PROSE: Venusian Lullaby)

Interaction with other species
When the Kotturuh brought mortality to the universe, the Great Vampires were the only beings too powerful to be stripped of their immortality altogether by the Kotturuh. Instead, the two species, being of about equal power, were forced to come to an agreement; the Kotturuh forced the Vampires' immortality to become reliant on stealing the life of mortal beings, thus making them into agents of death in their own right. Melody Malone noted that this made them "about as popular as a Weeping Angel at a wedding". (PROSE: The Guide to the Dark Times)

Richard Francis Burton hypothesised that the Great Houses obtained the ability of regeneration by intentionally modifying themselves with the Yssgaroth "taint". (PROSE: The Book of the War) One of the ROO texts revered by the Cult of Rassilon the Vampire claimed that Rassilon allowed himself to be bitten by a Great Vampire and was a vampire himself at the end of his life. (PROSE: Goth Opera)

War with the Time Lords
The ferocity and resilience of the Vampires made their defeat very difficult, even for the Time Lords, but nevertheless, the early Time Lords, under the reach of Rassilon, engaged on a campaign of extermination against the creatures. (TV: State of Decay) They waged the lengthy Eternal War to drive them back. (PROSE: The Pit) Since conventional weapons were virtually useless, Rassilon ordered the construction of bowships to exploit the one weakness of the Vampires — their vulnerability to being impaled through the heart. (TV: State of Decay)

Sometime during the war, the Dalek Time Squad captured a Great Vampire by attacking a coffin ship that was transporting one. The Prime Strategist and Scientist experimented on it, extracting its DNA to create the Dalek Symbiont. This Dalek bearing the taint was, however, short-lived, as the last of the Kotturuh, Inyit, used the last of her energy to pass judgment upon it and award it a lifespan of mere moments. (PROSE: All Flesh is Grass)

During the War, entire worlds were turned into laboratories of cruelty where the Yssgaroth destroyed the bodies of the inhabitants until only their nervous systems remained, alive and in agony but without any hope of help. (PROSE: The Book of the War) Every thirteen local years, their servants on each world would round up a thirteenth of the population and ship them to the Vampires' galactic headquarters in the Blood Citadel of Alukah, where they would be harvested for blood. (PROSE: Predating the Predators)

End of the War
Though billions of people were killed and whole star systems were destroyed, (PROSE: The Pit) the Time Lords were finally able to push the Yssgaroth back into their own universe, and the outlets to their universe were blocked and reinforced by containment shells disguised as planets, including Earth. (PROSE: Interference)

At the end of the war, the numerous "fallen" worlds which had found themselves in thrall of the Yssgaroth were retro-annulled by the Great Houses at the end of the war. (PROSE: The Book of the War)

Though the Time Lords were able to find and destroy all other Yssgaroth, the swarm leader was able to escape. (PROSE: Interference) This sole survivor hid in E-Space, using his great power to draw the ship Hydrax with him. He turned the three humans on this ship into vampires to feed and serve him for a thousand years until the Time of Arising. He would ultimately be killed by the Fourth Doctor and Romana II before he was able to fully awaken, long after the War. (TV: State of Decay)

One of Rassilon's titles was "Conqueror of Yssgaroth". (AUDIO: Zagreus) His throne appeared to be made of the skeletons of giant bats. (PROSE: Christmas on a Rational Planet) By the time of the Doctor and Romana, the Great Vampires and their history were not widely known on Gallifrey. However, the Doctor had heard distorted versions of the tale from an old hermit, and basic instructions were still included in the oldest part of the TARDIS databanks — the Record of Rassilon. (TV: State of Decay)

Lingering influence on the universe
Since they had emerged at the beginning of history, the Yssgaroth taint remained in the fabric of the universe even after their defeat; it couldn't be removed without unweaving time itself. (PROSE: The Book of the War) Additionally, after plugging the last hole to the Yssgaroth's universe with an artificial planet, the Engineer murmured to himself that he hoped no one would ever try drilling through to the core, (PROSE: Interference) a hope that the Inferno Project proved to be misplaced. It resulted in Stahlman's ooze being released, causing humans to become tainted and mutate into bestial Primords. (TV: Inferno)

Various lesser vampires, corrupted members of separate species, survived on many planets in the universe, such as Earth's vampires. Although Time Lords of later eras were sworn to destroy any such vampires on sight, small populations continued to exist, hiding in obscurity. For example, the Eighth Doctor met a coven of vampires in San Francisco in 1997. Befriending their leader, the thousand-year-old Joanna Harris, he ended up creating an antidote to the "V Factor" and purging her of vampirism. (PROSE: Vampire Science) A number of Mal'akh also existed on Earth throughout its history, with various secret orders being dedicated to fighting them. (PROSE: The Book of the War) Sutekh awakened them in great numbers in the 15th century, using them as pawns to demonstrate to the Great Houses that the Osirians had the power to upset their precious history. (AUDIO: Coming to Dust)

Temporal warfare
As the universe the Yssgaroth had tried to conquer began to be convulsed by time war, the knowledge of how to tap into the Great Vampires' universe was exploited by other parties, making the Vampires unwitting pawns of other conflicts.

During the War in Heaven, the Cold could suck its target into another universe, where it would be destroyed by the inhabitants. Those creatures sought to enter the universe through the Cold, attacking it with their gigantic black wings, enormous clawed hands, and huge teeth. One's face was the size of a Drashig. (PROSE: Interference) Lolita once pressed against the Very Fabric of Time and Space to show Count Dracula a glimpse of the Yssgaroth wanting to enter the Spiral Politic. (PROSE: A Bloody (And Public) Domaine) Jendrickenses speculated that the Yssgaroth would be able to return through the Grandfather's Maw. (PROSE: The Brakespeare Voyage) The Yssgaroth had its own agenda during the War, voluntarily "gazing upon" a living time machine to grant her the power to become a great Adversary to the Yssgaroth's old enemies, (PROSE: Preternatural Nights) resulting in the creation of Lolita. (PROSE: The Book of the War)

During the Last Great Time War, the Time Lords, at the command of Cardinal Ollistra, released the Great Vampires from their universe to fight off a fleet of Dalek saucers. Despite the War Doctor's protests, Councilor Voltrix proceeded to open a rift, allowing them through. The memories of this event proved the Ninth Doctor's memories of the Time War were authentic. (COMIC: The Bidding War)

Yssgaroth influence on Earth
The Yssgaroth's universe continued to press itself against universe of Earth in the form of a "reservoir of evil and pain", (PROSE: Preternatural Nights) also called a "reservoir of pain" or "river of evil" by Doctor Colin Dove. The evil force native to that non-physical realm could influence sensitives directly when they approached "synapses" or "leprous houses", specific places where the connection between the physical universe and the reservoir of evils. On 13 August, 1945, the force possessed young Daniel O'Kane and had him murder his mother, father and sisters. Daniel was the most sensitive person known to Dr Dove until Peter Russell. Dr Dove, somewhat sensitive himself, wished to unleash the force in 1994 using Daniel and Russell at perihelion. He became obsessed with learning what would happen if this came to pass.

By August 1994, the force had killed nine people through Daniel before killing William Bruffin, who they reanimated briefly. Dr Dove saw this as a sign that it was almost perihelion and time for Daniel and Russell to meet. The force killed Dr Dove when he was no longer of use and was breaking through before Daniel, in a moment of clarity, jumped in front of Russell's blade and saved Dr Liz Shaw. Daniel's death meant that the force could not be unleashed. The force still had a connection to the physical world, however, as shown through a psychic connection between Russell and Patient One. (HOMEVID: The Zero Imperative)

After the Greth was banished into the Void by the Clock-People, it met a being it later referred to as "its patron", (PROSE: Out of the Box) the Yssgaroth. (PROSE: Preternatural Nights) Recognising a kinship between the Greth's nature and its own, the Yssgaroth took it under its wing, teaching it how to corrupt other beings' biodata instead of simply killing and replacing them. It then helped the Greth return to the universe through the Infernal Depths, with instructions to make contact with some of the "patron"'s agents on Earth. However, the Greth was defeated by P.R.O.B.E. before its world-domination plans could come to fruition. (PROSE: Out of the Box)

After Archie MacTavish fell through a half-formed dimensional portal in 2018, he became trapped in the space between dimensions, pressed between the border of his native universe and the dark universe of the Yssgaroth. The Yssgaroth reached out to him, turning him into a vampire to heal his fatal wounds and helping him return to his home universe as its agents. A Perihelion of great magnitude, a period when contact between the two universes, was imminent, and Archie intended to take advantage of it to organise a grand ritual in London that would allow the Yssgaroth to fully reenter the universe. He tried to weaken and distract the Preternatural Research Bureau, the organisation which had previously employed him, and which he thought would be the only real threat to his and the Yssgaroth's plans. P.R.O.B.E. eventually managed to disrupt the ritual and subdue Archie, barring entry to the Yssgaroth, although Az felt that the Yssgaroth had not given up, and immediately started pressing against various other gateways across the universe once this one was closed to it. (PROSE: Preternatural Nights)

Alternate timelines
During one of Romana II's, Leela's and Narvin's trips to alternative Gallifreys, they visited one where Rassilon was killed by the Great Vampires after completing the transduction barrier. The Vampires then darkened the barrier to block out all light so they might live safely on Gallifrey. Over the next millennia the vampires gradually took over the True Lords, until the battle between the vampire Lord Prydon and the True Lady Magestrix Borusa. During this battle, with Leela's help, Narvin and Romana helped Borusa and recaptured the transduction barrier, increasing the light levels allowed to pass through and destroying the Vampires. (AUDIO: Annihilation)

Behind the scenes

 * About the use of the Yssgaroth in the Faction Paradox series, Lawrence Miles said, "The idea of a formless horror from before the dawn of time is generic, but 'Yssgaroth' is the best name I've ever heard, so I thought it'd be better to get Neil's permission than to use a completely different word for the same thing." (REF: Bernice Summerfield: The Inside Story)
 * In Gallifrey: A Rough Guide, the terminology used subtly differs from those used in other stories: the species are only ever referred to as "vampires" or "Yssgaroth", while the leader is called "the Great Vampire" — instead of "Great Vampires" referring to all members of the species and the leader being the "King Vampire".

Information from invalid sources
According to At the Mouth of Madness, the ancient Vampire Gods were home to the Weapon-Worlds of the lost galaxy of Nosfera II. This could be accessed through a wormhole called the Hellmouth, which the Daleks attempted to enter to verify the stories. However, as the Dalek fleet prepared to enter the wormhole, a hundred thousand Chiroptera came shrieking out and tore the fleet to pieces. Legend said that their screams could still be heard echoing through the Astral Fog. (NOTVALID: Bats Out of Hell!)

According to Doctor Who: Creatures and Demons, the Plasmavores were descended from the Great Vampires. However, that source is considered invalid by this wiki.