Suren, who frequently goes by Wren, is the 18-year-old changeling queen of the Court of Teeth. She escaped to the mortal world after a brutal childhood defined by torture at the hands of her parents. Deeply distrustful and fiercely protective of her autonomy, she lives a feral existence observing the human family she once lived with. She carries deep physical and emotional scars from the magical golden bridle she was forced to wear.

Oak is the 17-year-old Prince of Elfhame and heir to the throne. Raised by the exiled general Madoc, he hides a sharp mind and martial prowess behind the facade of a carefree trickster. He journeys into the north on a dangerous quest, seeking Suren's unique power to assist him against Lady Nore while keeping his own motives closely guarded.

Lady Nore is the beautiful and ruthless ruler of the Court of Teeth. She values ferocity and ambition above all else, harboring deep resentment toward the High Court of Elfhame. Using ancient magic extracted from the bones of the first queen, she seeks to build an unstoppable army of monsters and expand her power.

Bogdana is an ancient storm hag with immense power who serves Lady Nore. She has a terrifying, spindly appearance with mushroom-pale skin and claw-like fingers. Despite hunting Suren across the mortal world on Lady Nore's orders, she remains one of the few figures from the Court of Teeth to have shown the young queen any kindness during her torture.

Madoc is a ruthless, battle-hardened redcap faerie and the former Grand General of Elfhame. Despite his treacherous history of staging coups against the crown, he deeply loves his foster son, Oak. He currently finds himself a captive of Lady Nore at the Ice Needle Citadel, prompting Oak's desperate rescue mission.

Tiernan is an Elfhame-approved guard assigned to protect Prince Oak. A former spy for the Court of Shadows, he is disciplined and highly efficient with a knightly demeanor. He struggles with lingering feelings and guilt regarding his former lover, who now travels with them as an unwilling captive.

Hyacinthe is a former soldier who allied with Madoc during a past rebellion and is now cursed to live in a part-falcon form. Controlled by a magical golden bridle, he travels as a prisoner with Oak and Tiernan. He yearns for freedom and attempts to sow doubt among the group regarding Oak's true intentions.

Lord Jarel is a faerie noble from the Court of Teeth and the partner of Lady Nore. Together with Lady Nore, he orchestrated the traumatic reclaiming of Suren from the mortal world, forcing her back into Faerie and subjecting her to a life of cruelty.

Queen Annet is the ruler of the Court of Moths. She governs a dangerous territory that Oak and his companions must travel through. She is a cunning leader who enjoys hosting extravagant revels and enforcing strict punishments in her domain.

Jack of the Lakes is a kelpie who takes the form of a steed to transport Oak and his companions. Opportunistic and untrustworthy, he plays dangerous games of loyalty during their stay at the Court of Moths.

Habetrot is the royal seamstress at the Court of Moths. She possesses the unique magical ability to weave garments from the dreams and hidden desires of her clients.

Gwen is a human girl imprisoned in Queen Annet's dungeons at the Court of Moths. Her predicament reminds Suren of her own past and her foster sister, prompting the young queen to intervene.

Hurclaw is a troll king desperate to break an ancient curse that turns his people to stone in the sunlight. He allies with Lady Nore in the hopes that her newfound power can free his subjects.

Jude is the High Queen of Elfhame and Oak's older sister. Though she remains off-page, her past decrees heavily influence the current state of Faerie politics, particularly the specific command that forces Lady Nore to obey Suren.

Cardan is the High King of Elfhame, ruling alongside his wife, Jude. He is a powerful figure in the background whose past conflicts with the Court of Teeth shape the present danger in the north.

Bex is Suren's human foster sister, or "unsister," from her brief time living in the mortal world as a child. Suren still watches over her from afar, cherishing the memory of their childhood games.

Gorga is the leader of a cursed troll village in The Stone Forest. Suspicious of outsiders, he offers Oak and his companions poisoned tea during their treacherous journey toward the Ice Needle Citadel.