Livira is a young girl from a desolate region called the Dust who becomes a trainee librarian in Crath City. She possesses a photographic memory and an insatiable curiosity that constantly puts her at odds with societal expectations. Defying the rigid prejudices against her people, she quickly learns to read and write while exploring the forbidden, uncatalogued sections of the massive library.

Evar is a young canith—a wolf-like humanoid—who is trapped with his adoptive siblings in a single, two-mile-wide chamber of the library. While his siblings emerged from a magical device called the Mechanism with specialized skills, Evar returned with only a faint memory of a woman he must save. Lacking combat or academic specialties, he acts as the empathetic peacekeeper among his increasingly volatile family.

Master Davris Yute is a pale, gray-clad deputy librarian in Crath City. He lives in a tower-shaped home on the mountain with his housekeeper and a massive cat. Operating with an agenda that often conflicts with the city's nobility, he sponsors Livira's education and encourages her to explore forbidden knowledge to understand the cyclical destruction of civilization.

Malar is a heavily scarred, foul-mouthed soldier who operates in and around Crath City. Though outwardly cynical and dismissive, he adheres to a strict personal code of ethics. He becomes an unlikely bodyguard for Livira, initially claiming he only helps her out of debt or for pay, though he develops a genuine protective instinct toward her.

Clovis is the only female among Evar's adoptive canith siblings. She entered the Mechanism as a child while fleeing a human massacre that wiped out her settlement. Emerging with extensive combat and tactical skills, she is consumed by a desire for revenge against humanity and views the world entirely through the lens of war and betrayal.

Kerrol is one of Evar's adoptive canith siblings, trapped in the isolated library chamber. Having learned psychology from his time inside the Mechanism, he constantly analyzes and manipulates those around him, often using Evar's fears to track the monstrous Escapes that invade their home.

Starval is one of the five canith children raised by automatons in the library chamber. He emerged from the Mechanism with the specialized skills of an assassin, making him a stealthy and dangerous asset during the siblings' battles against the Escapes.

Mayland is the eldest of the five canith siblings. He studied history and mythology while inside the Mechanism, particularly tales about the library's ancient origins, but vanished and is presumed missing or dead by his siblings.

The Assistant is a nearly invincible automaton that maintains the isolated library chamber. She serves as a cold but dedicated caretaker for the five lost canith children, raising them after they emerged from the Mechanism into an empty world.

The Soldier is a stoic automaton assigned to defend the library chamber where Evar and his siblings live. Typically reserved and indifferent to daily activities, he displays sudden, fierce protectiveness when the children are threatened by Escapes.

Arpix is a trainee librarian in Crath City who studies alongside Livira. Indoctrinated in the city's accepted histories, he initially struggles to understand Livira's interest in fiction but remains a steadfast friend and accomplice when she breaks library rules.

Yamala is the current head librarian of Crath City. She controls the library's complex cataloging systems, altering the index to maintain her absolute authority over the flow of information both within the building and throughout the kingdom.

King Oanold is the aging monarch of Crath City. He enforces strict censorship by maintaining lists of approved books, actively opposing the integration of refugees from the Dust, and suppressing any narratives that challenge his political authority.

Lord Algar is a wealthy noble in Crath City who oversees the allocation of children into the workforce. He holds deep-seated prejudices against individuals from the Dust and views Livira's presence in the library as an affront to the social order.

Serra Leetar is a young noblewoman appointed as a junior diplomat in King Oanold's court. Her elevated status contrasts sharply with the struggles of the trainees and refugees living in the lower tiers of Crath City.

Meelan is a trainee librarian in Livira's study group. Despite his noble lineage, he studies alongside commoners and bravely attempts to shield Livira during a sudden canith attack in the city plaza.

Carlotte is a trainee librarian who shares meals and study assignments with Livira. She helps orient Livira to the overwhelming size of the library and explains the social biases encoded in the king's approved reading lists.

Jella begins as a trainee librarian in Livira's study group and eventually becomes a professional bookbinder. She survives the violent siege of Crath City by hiding within the deep library corridors.

Master Logaris is a teacher who manages the young library trainees. He assigns Livira's group the difficult task of locating a specific book within two days, inadvertently pushing Livira to explore the uncatalogued sections alone.

Ellis is a high-ranking librarian who views Livira as a political threat. Livira shadows him through the restricted chambers to uncover the hidden Mechanism room used by the elite staff.

Aunt Teela is Livira's guardian in the barren settlement of the Dust. She breaks up Livira's fights and assigns her daily chores before a devastating canith attack upends their lives.

Ella is a woman living in the Dust. She gives young Livira a ball of twisted wind-weed that contains a mysterious image of a young boy.

Katrin is a girl from Livira's settlement in the Dust. She challenges Livira's desire to visit Crath City, pointing out that the city's residents actively exclude outsiders.

Acmar is a larger boy living in the Dust. He gets into a physical altercation with Livira over a mysterious scrap of paper she finds in the dirt.

Salamonda is Master Yute's friendly but formidable housekeeper. She provides Livira with fresh clothes, food, and basic care when the young girl first arrives at Yute's mountain home.

Hiago Abdalla is the senior alchemist at Crath City's laboratory. He warns visitors about the volatile chemical weapons stored in his facility following a sudden industrial accident.

The Raven, also known as Edgarallen, is a winged automaton guide residing in the ancient sections of the library. It steals Livira's map and inadvertently leads her to the forbidden portal known as the Exchange.

Volente is a massive, black hound automaton used as a specialized guide within the library. Livira secretly utilizes him to bypass locked doors and access restricted chambers during fires and attacks.

Wentworth is a massive cat residing in Master Yute's home, adding to the eccentric and comfortable atmosphere of the librarian's private quarters.

Irad is a legendary historical figure and descendant of the first murderer. He is credited with founding the original library and creating the automaton assistants to preserve its infinite knowledge.

Jaspeth is a historical figure who warred with his brother over the control of knowledge. His followers believe that destroying the library is necessary to break civilization free from the constraints of the past.