Cassia is a 17-year-old girl with dark hair and green eyes. She is initially sent to work camps in the outer regions of the Society, performing hard labor while harboring a fierce determination to find Ky. She is highly observant and secretly carries contraband items—specifically a compass and blue tablets—which symbolize her growing rebellion against the rigid rules she grew up with in the Boroughs.

Ky is a 17-year-old boy with dark hair and blue eyes who operates as an Aberration and decoy on the front lines. Raised with a deep appreciation for poetry and art, he carries a painful past involving the destruction of his home village. He remains cautious and highly suspicious of authority figures, preferring to rely on his own survival skills in the canyons and wilderness.

Xander is a confident, popular 17-year-old boy with blond hair and blue eyes. As a medic and Cassia's official Match from the Society, he represents the safety of her former life in Oria Province. Despite the physical distance between them, he goes to great lengths to provide Cassia with resources for her survival in the outer regions.

Indie is a tall, red-haired Aberration working in the same camp as Cassia. She is fiercely independent and calculating, unafraid to bend or break rules to achieve her goals. Driven by a desire to locate the mythical Pilot and the Rising, she proves to be a resourceful but unpredictable companion during the journey into the canyons.

Vick is an Aberration and a decoy fighting on the front lines against the Enemy. He possesses a natural ability to command, often finding other decoys looking to him for instructions despite his reluctance to take charge. He is pragmatic, teaches survival skills like fishing to the younger boys, and holds onto a private history involving an Anomaly girl.

Eli is an optimistic, roughly 13-year-old boy with dark curly hair who is sent to act as a decoy. Having lost his parents to an illness in Central, he relies on older figures for protection but maintains an inquisitive spirit. He asks constant questions and shows a high sensitivity to the danger around him.

Hunter is a farmer and an Anomaly living entirely outside of the Society's control. He marks his skin with blue lines that represent his connection to the natural world. Having lived independently for years, he serves as a knowledgeable guide and challenges the teenagers' understanding of institutions and freedom.

Aida is Ky's aunt, who took him in after the devastating destruction of his home village. She provided him with his family's silver compass, a vital artifact that connects him to his past.

Patrick is Ky's uncle in the Borough. He quietly subverts the Society's strict control over history and writing by secretly trading old writing for an illegal scribe.

Laney is an Anomaly girl from Camas Province whom Vick loved deeply. Their unauthorized relationship directly led to his Reclassification and current status on the front lines.

Cassia's deceased grandfather continues to act as a guiding force in her life. His memory and the poetry he secretly shared with her provide Cassia with emotional strength and a framework for resisting the Society.

Sarah is Hunter's deceased young daughter. Her tragic death and subsequent burial bring the traveling teenagers together with Hunter and grounds the harsh reality of life outside the Society.

Matthew is Aida and Patrick's son, who died before Ky came to live with them in the Borough. His absence shapes the grief of Ky's adopted family.

Bram is Cassia's younger brother back in the Society. She misses him dearly, and his memory influences how she cares for younger members of their group in the wilderness.