Callum

Callum was a Novice of the Plume Coteries, native to their infinite Library. Alongside fellow Novice Maritsa, he became a fugitive from his own people to save Coloth. (PROSE: )

Origins
Like Callum, Maritsa, as a born member of the Plume Coteries, was "human-ish", that is to say, a posthuman. Though mostly human-like in biology, this involved a few discrepancies, such as the native ability to read any language. He became a Novice and, at some point, acquired a map of the Library which had been created by Auteur during his stay in the Library centuries prior. (PROSE: )

Rescuing Coloth
At some point, a teenaged Callum and fellow Novice Maritsa became aware of Coloth, one of the subjects of the Plume Coteries' programme of Time-Ladling dead eyewitnesses to historical events out of time, transferring a biodata-print of their consciousness into a holo-cube, and then interrogating them. Normal procedure would have been to destroy the cube once Coloth's interrogation was done, but Maritsa and Callum felt strongly that this would be wrong, particularly as Coloth had been killed before his time in his original lifetime. The two eventually conspired to "check him out of the restricted section" and then "never gave him back".

Originally, the trio were meant to quickly meet and befriend a dimension-travelling Birdhemoth, (PROSE: ) Rich, (PROSE: ) but Auteur interfered with this, retroactively deleting Rich from existence. As a result, Maritsa, Callum and Coloth instead spent over three months as fugitives within the Library itself, camping out in unexplored floors and using Callum's map to find vending machines and bathrooms from which they could salvage food and water. They gradually grew closer in the process, despite their uncertainty about the future. (PROSE: )

Auteur and Naimon
Eventually, their camp was found by Master Librarian Naimon. He wounded Callum in the thigh with a crossbow-bolt, and eventually managed to capture the three. Naimon searched the Novices, and found Callum's map, on which the kids had earmarked Floor 899,167,435,042 as their next destination. As this Floor had been incompletely explored by Naimon's ancestor Master Librarian Roland, Naimon decided to use the map to finish the job and reap twice the glory before he brought his captives back to the Plume Coteries. On the way, taking advantage of his overconfidence and self-inflicted poor eyesight, Maritsa and Callum tricked Naimon into walking into an empty elevator shaft, killing him. With Coloth's help, they made their own way down, still intending to take advantage of the "village-sized" bathrooms to wash and restock on water.

After getting there, they discovered that the map was incomplete because Floor 899,167,435,042 was where Roland had confronted Auteur centuries prior; Roland had ended up burning the entire Floor down in an effort to kill Auteur. The blood spilled by Naimon's death allowed Auteur to create a new body for himself. After blithely telling the teenagers about the ways in which he had interfered in their lives according to his sense of what made for a better story, he attempted to complete the ritual Roland had interrupted centuries prior, which was meant to summon the Bookwyrm, a "god-serpent" deeply rooted in the structure of the Library. He succeeded, only for the Bookwyrm to reveal it had no intention of being controlled, and eat Auteur right in front of the baffled teens. (PROSE: )

During their brief encounter, Auteur admitted that his retconning-out of Rich had been a "rushed job" which probably wouldn't "stick", predicting that the teenagers would find him again sooner or later. (PROSE: )

Physical appearance
As a Novice Bookkeeper, Callum wore simple brown robes. (PROSE: )