Essun is a powerful orogene whose right arm petrifies into stone following extreme physical exertion. She journeys with the surviving members of the Castrima community toward the city of Rennanis. Her primary motivation remains finding her missing daughter while learning to accept assistance from her peers.

Nassun is a young orogene who has endured significant physical and emotional displacement. Feeling alienated by the hostility directed at people with her abilities, she travels with a Guardian in search of a safe haven. She possesses an intuitive grasp of magic and the ancient obelisks scattered across the planet.

Schaffa is a Guardian tasked with controlling orogenes. He has begun making autonomous choices that cause him severe physical pain due to a corestone embedded in his brain. He dedicates himself to protecting Nassun, offering her the unconditional care she has long sought.

Hoa is an ancient stone eater who accompanies Essun on her journey and acts as the narrator of the story. In flashbacks to the distant past, he is known as Houwha, a genetically engineered tuner created by the empire of Syl Anagist to interface with the Plutonic Engine. He maintains a calm demeanor while secretly influencing events to aid his companions.

Father Earth is the sentient, living consciousness of the planet. Angered by ancient humanity's attempts to exploit his core for unlimited magic, he exercises control over the Guardians and actively works against those who utilize the obelisks.

Ykka is the orogene leader of the Castrima community. She focuses on long-term survival and building an inclusive society where orogenes and stills can coexist. Her pragmatic leadership style sometimes causes friction with those focused strictly on individual survival.

Lerna is a healer traveling with the Castrima survivors. He provides practical medical advice regarding physical injuries and mutations caused by orogeny. He cares deeply for Essun and supports the community during their harsh desert crossing.

Steel is an ancient stone eater who encourages Nassun's darker impulses. He holds a deeply pessimistic view of existence due to his prolonged lifespan. He guides Nassun toward ancient transportation networks while advocating for planetary destruction.

Jija is Essun's husband and Nassun's father. His intense hatred and fear of orogenes drove him to murder his young son upon discovering the boy's abilities. His inability to accept his children's true nature leaves a lasting traumatic impact on his family.

Kelenli is a woman living in the ancient city of Syl Anagist who possesses abilities similar to the tuners. Raised as a social experiment alongside Conductor Gallat, she serves as a lorist who secretly educates the tuners about their true history and the oppressive nature of their society.

Conductor Gallat is an overseer of the Plutonic Engine project in ancient Syl Anagist. Raised alongside Kelenli, he possesses pale skin and icewhite eyes, traits that cause other conductors to look down on him. He operates within the oppressive system to maintain his power.

Maxixe is a former Fulcrum orogene who has suffered severe physical injuries, including the loss of an eye and both legs. He leads a small group of survivors in the wilderness. After recognizing Essun from their shared past, he negotiates for his group to join Castrima.

Danel is a former Rennanis general who surrendered to Castrima. She is originally from the lorist caste and possesses a deep interest in witnessing history as it unfolds. She volunteers to accompany Essun on her final mission.

Uche is a young orogene child whose abilities were discovered by his father. His tragic death catalyzes the splintering of his family and drives the primary conflict between his surviving relatives.

Umber is a Guardian stationed at Found Moon. He adheres strictly to the mandates of his order and attempts to stop Nassun, leading to a brutal clash with his former colleague.

Nida is a Guardian at Found Moon who uses her abilities to negate orogeny. She works to neutralize threats according to Guardian doctrine but is swiftly defeated during the conflict.

Gaewha is a genetically engineered tuner who operates within the Plutonic Engine project. She communicates covertly with her fellow tuners through the earth and experiences a radical awakening upon learning the true history of her people.

Tonkee is a knowledgeable and curious member of the Castrima community. She offers practical advice to Essun regarding her search for Nassun. She remains a loyal traveling companion throughout the grueling march to Rennanis.

Hjarka is a fiercely loyal fighter and member of Castrima. She stays close to Essun during the community's difficult relocation and helps defend the group against raiders in the wilderness.