Plume Coteries' Library

The Plume Coteries' Library, often simply the Library, was "one of several places that claim[ed] to be the biggest library in the Universe". It was tended by the Plume Coteries, hence their nickname as "Bookkeepers", and allegedly had a copy of every book ever written. (PROSE: ) The Bookwyrm once summed it up as "it's not quite the Library of Babel, but it's home". (PROSE: )

Nature
The Library was "hyperdimensional" and was "infinitely tall, infinitely wide". It was located outside the Universe proper, being one of the many mini-worlds, pocket dimensions and bottle universes which "orbited" it; there were two known entrances, the Cosmic Gate (which admitted visitors from the Universe proper) and the Void Gate, which admitted interdimensional travellers from the wider Omniverse. Its endless shelves were stocked with an infinite amount of books, including, in theory, "infinitely many copies of any given book".

The infinitely-spacious floors were connected via stairways and elevators at regular if miles-long intervals, and occasionally presented such amenities as bathrooms and vending machines, the main sources of food and water. The Library also contained "vast computer data-banks, and terminals that [were] available to the public", although the Bookwyrm once cautioned that "the monitors [had] been known to avail themselves to the public, and should only be approached in the direst of emergencies". (PROSE: )

Being outside the universe proper, the Library and its denizens were able to interact with people and events related to the War in Heaven (PROSE:, ) even after they functionally became contemporary with the post-War era. Indeed, for a long time, the Bookkeepers remained unaware that the conflict was over, due to willful misinformation spread by the Bookwyrm. (PROSE: )

Origins
The Library was so ancient that "practically no one" remembered where it had come from, although there were various legends about it, some of which spoke of a Creator figure, an archetypal architect-librarian who had designed the Library would return someday in its hour of need. The Bookwyrm was one of a few beings to remember the Library's true origins, but claimed that it "wasn't that interesting"; on one occasion, the Bookwyrm listed frivolous hypothetical answers to the question to a human listener in order to demonstrate the matter's irrelevance. These included it being "conceived by the ghost of Jorge Luis Borges", that it "grew from the seed bismuth", or that "it's simply always been here". Some time later, however, it let slip that if the human could understand the Bookwyrm's own true name it would "a lot more insight into the nature of the Library than [they] realise[d]". (PROSE: )

The coming of the Bookkeepers
"Just before" the Cosmic War, the Plume Coteries, a posthuman group who had found and "tamed" the dimension-crossing Birdhemoths, found the Library by chance. They began exploring it, and, shortly after the War properly got started in the main universe, realised that they could exploit their discovery to become a respected group in universal politics. They began to sort through the infinite collections in an effort to compile "the complete and sufficient list of all true history books", hoping that such a collection might be useful onc the War was over as a schematic from which to repair all the damage to history that Time was accumilating as a result of the temporal warfare. In the process, they began burning books which they considered heretical or otherwise dangerously inaccurate. (PROSE: )

Auteur in the Library
After his involvement in the rescue of Grant Markham from the Point of Know Return, Auteur, who had become stranded outside the universe in the post-War era, (PROSE: ) got Lady Aesculapius to drop him off at the Library. Entering through the Void Gate, he revived an old alias of his, posing as a long-lost Mapper who'd returned at last to the universe, and wished to map out the Library itself. Other visitors to the Library on that day included Professor Castarban, Jark Haine, the Last of the Lords Collective, Laetitia and Olivia Marshall, Ojo the Unlucky, the Scarlet Arisrian, and King Selvabon.

The so-called "Last of the Mappers" remained with the Bookkeepers for twenty years, leading many Stocktaking Parties; for the last ten years, he became a mentor to a young Master Librarian who would go down in legend, Master Roland. His true aim was to find and subdue the Bookwyrm, and then ride him "into glory" as he made a triumphant return to the main universe. However, when he attempted to sacrifice Roland's firstborn child to power a ritual to summon the Bookwyrm on Floor 899,167,435,042, Roland finally saw through his charade, and, in a desperate effort to stop him, set fire to the entire Floor. (PROSE: )

The Coloth affair
258 years later, as part of their efforts to check the accuracy of all historical records in the Library, the Bookkeepers used Time-Ladle technology, (PROSE: ) which they had obtained from the Great Houses during the War in Heaven, (PROSE: ) to "ladle up" biodata-prints of the long-dead, uploading them to holo-cubes for interrogation. At some point, this program turned its attention to Coloth, a young alien who had been killed early relative to his scheduled historical death (PROSE: ) in the aftermath of the War Chief incident, due to the Time Lords foolishly returning one of the Aliens' brainwashed soldiers to his planet without undoing all of his mental conditioning. (PROSE: ) Callum and Maritsa, two Novice Bookkeepers, decided to rescue him. In the original version of history, they quickly escaped the Library thanks to the help of the Birdhemoth Rich, but history was preemptively rewritten by Auteur during his aforementioned stay in the Library. In the rewritten timeline, they spent over three months being chased through the Library by Master Librarian Naimon. Eventually, he died while trying to get to Floor 899,167,435,042, where his blood allowed Auteur to regenerate from the ashes at long last. After briefly introducing himself to the three young people, the reborn Auteur completed his original ritual to summon the Bookwyrm, only for the Bookwyrm to eat him. (PROSE: )

Involvement in the White Canvas plot
When the painted warriors attacked the 10,000 Dawns, they stole every copy of The Book of the Enemy therein to cover their tracks. However, the Emissary advised Graelyn Scythes, Archimedes Von Ahnerabe and Lady Aesculapius that a copy could still be found in the Plume Coteries' Library. Travelling there via crystalline incision portal, they happened upon Coloth, who got Marissa, (PROSE: ) whose name had yet to be metatemporally retconned to Maritsa even though this was a later event in her timeline, (PROSE: ) to consult the catalogue. Marissa gave them a glowing library card which would direct them to the book despite the place's unthinkable size, but advised Coloth to go with them because the book itself might prove dangerous. After locating it, the group discovered that the painted warriors were servants of the Original Mammoths and travelled via another portal to the alter-time realm the mammoths called home in the context of the war. (PROSE: )