Ella is an 11-year-old girl from a family of Conjurors in New Orleans. As the first Conjuror student ever admitted to the elite, sky-based Arcanum Training Institute, she faces immediate suspicion and isolation from her Marveller classmates. She practices naturalistic magic closely connected to the earth and the Underworld. Desperate to earn the acceptance of her peers, she eagerly seeks to discover her "Paragon" (her specific magical gift) to prove she belongs at the academy.

Brigit is a blonde Arcanum student who grew up in New York City among non-magical people, completely unaware of her magical heritage. She resents being forced to attend the sky academy and frequently attempts to run away back to her normal life. She compulsively knits quilt squares that often contain magical properties. Because of her surly attitude and unusual upbringing, she struggles to fit in with the other Marveller students.

Jason is a Level One student at the Arcanum who comes from a large family with many older siblings already attending the school. He knows the complex layout and rules of the academy well and shares this insider knowledge with Ella and Brigit. He possesses the Paragon of Sound, which allows him to speak to animals, and he spends much of his free time helping maintain the school's menagerie.

Known as the Ace of Anarchy, Gia is an infamous rebel and former circus illusionist. She possesses a rare and chaotic marvel that allows her to see and manipulate the threads of the universe. Imprisoned for eleven years after an accidental death occurred during one of her performances, she harbors deep resentment against Marveller rules and plots vengeance against the society that locked her away.

Masterji is a welcoming Arcanum teacher who instructs a class on elixirs and possesses a Paragon of Taste with a spice marvel. He acts as Ella's mentor, showing sympathy for the prejudice she faces at the academy. He actively tries to support her education, though mysterious magical gags choke his voice whenever he attempts to share certain suppressed historical secrets with her.

Sebastien is Ella's father and the Grand High Walker, a position of massive responsibility that involves managing the entire Underworld and its various realms, including its magical prisons. He wears a traditional top hat and approaches the world with practical wisdom, believing that Conjuror children must learn to survive and adapt in both the earth and sky environments.

Aubrielle is Ella's mother and a highly gifted Conjuror. She holds deep suspicions about the Marveller sky world and worries that attending the Arcanum will negatively alter her daughter's nature. Her protective instincts stem largely from a childhood tragedy when her twin sister vanished during a trip to a sky city.

Sera is Ella's aunt, godmother, and the newest faculty member at the Arcanum, hired to teach the Conjure Arts. She possesses impressive magical skills that command immediate respect from her wary students. She acts as a grounded guide for Ella, explaining the shared history of their magic while handling prejudiced students with grace and dignity.

Celeste is Aubrielle and Sera's sister who possessed a great curiosity and enthusiasm for the sky cities. She vanished without a trace years ago during an excursion to the Marveller world, a traumatic event that severely impacted her family and caused Aubrielle's deep, lasting distrust of the Arcanum and its people.

Headmarveller Rivera is a Hispanic woman who serves as one of the two governing administrators of the Arcanum. She works diligently to maintain good public relations regarding the school's integration efforts. She frequently intervenes to help Ella feel welcome and actively manages roommate conflicts to keep the peace among the student body.

Headmarveller MacDonald is a Scottish man and co-administrator of the Arcanum. He attempts to reassure Ella that she belongs at the academy and publicly promotes harmony among the students. However, he remains strictly bound by procedure when serious conflicts or accusations arise, relying on formal disciplinary boards rather than personal judgment.

Dean Nabokova is the cold and reserved Dean of Discipline at the Arcanum. She harbors an implicit bias against Conjurors and heavily scrutinizes Ella's behavior. She readily accepts reports against Ella without demanding concrete evidence, assigning monitor spells to place the young girl under strict surveillance.

Dr. Winchester is an elderly professor who teaches divination studies. He takes an immediate dislike to Ella and strictly enforces school rules, frequently reprimanding her for minor or imagined infractions. He embodies the deep-seated prejudice that many older Marvellers hold against Conjuror magic.

Clare is one of Ella's original roommates at the Arcanum who successfully petitions to have Ella moved out of their quarters. She leads a clique of girls who are actively rude to anyone they deem different. She shares the conservative, anti-integration views of her politically powerful father.

Winnie is Ella's six-year-old younger sister. She shares the family's Conjuring heritage and actively participates in their naturalistic magical practices. She looks up to Ella and enthusiastically joins the family's holiday festivities when Ella returns home for winter break.

Feste is a harlequin clown doll who serves as Brigit's magical guardian. Enchanted by Brigit's late grandmother, he has secretly watched over Brigit since she was sent to live in a non-magical city. Once released from the closet, he provides Brigit with crucial information about her magical heritage and guides her to a pocket-box filled with family mementos.

Jefferson Lumen is Clare's father and an influential conservative politician in the Marveller community. He holds strong pro-segregation ideologies and actively campaigns to expel Conjuror influence from the sky cities, claiming his goal is to "Make the Marvellian World Light Again."