Confined to a single human body, Breq is the sole surviving segment of the artificial intelligence that once animated the troop ship Justice of Toren. She visits the remote, icy planet of Nilt to acquire a rare alien weapon to assassinate the Lord of the Radch. Moving through a foreign world where her lack of gloves and unfamiliarity with gendered pronouns single her out, she grudgingly rescues a former officer from her past. Breq misses the vast network of senses she once possessed and frequently hums a regional song to self-soothe.

Born into an ancient aristocratic house, Seivarden is a Radchaai officer who awakens after a millennium in a suspended animation pod. Finding her family extinct and her status erased, she drifts into substance abuse on Nilt until Breq rescues her. Initially arrogant and resentful of functioning as a servant, she slowly adapts to her circumstances. She struggles to comprehend shifting modern accents and relies heavily on Breq for basic survival.

Ruling the Radchaai empire for 3,000 years, Anaander Mianaai coordinates thousands of genetically identical bodies across numerous planets. As the supreme arbiter of Radchaai law, she directs the empire's aggressive expansion and religious assimilation. The annihilation of a planetary system centuries ago triggered an ideological fracture within her interconnected mind. She now operates a shadow conflict against herself, with different bodies secretly advancing opposing political agendas.

Stationed in the half-ruined marsh city of Ors, Awn commands the One Esk decade of ancillary soldiers. Born to a cook, she relies on meritocratic reforms to secure her position and feels insecure among her aristocratic peers. She adopts local dress and builds genuine trust with the lower-class Orsians, actively rejecting the prejudiced attitudes of the regional elite. Her ethical reservations regarding Radchaai expansion put her in direct conflict with her superiors.

Born into the famously eccentric and idealistic house of Awer, Skaaiat commands the Seven Issa decade on Shis'urna. Her aristocratic background provides her the security to openly criticize the empire's endless cycle of annexations without facing immediate reprisal. She pursues a romantic relationship with Awn and attempts to support the younger officer through intense political friction. Later in life, she serves as an Inspector Supervisor on a major palace station.

Operating the temple of Ikkt in Ors, the Divine serves as the spiritual and political leader of the Orsians. She advises her people to submit to Radchaai annexation to prevent their destruction and personally requests Awn's continued presence as an administrator. She meets regularly with Awn for tea, acting as a pragmatic mediator between the occupying forces and her resentful populace.

Serving as a flower-bearer in Awn's household temple, Daos Ceit grows up heavily influenced by the military occupation of her home. As an adult, she relocates to a palace station to work as an adjunct for the Inspector Supervisor. She wears distinctive commemorative pins tracking her associations and carries intense anger toward the Radchaai leadership over past atrocities.

A former medic from a non-Radchaai space station, Strigan lives in hiding on the mossy tundra of Nilt. She hoards illegal cultural antiquities, possessing a Garseddai weapon capable of bypassing Radchaai armor. Operating from a dark, lavishly furnished safehouse, she holds intense prejudice against the Radchaai, viewing them as a homogenous, brainwashed collective.

An unnamed child from a family of Nilter herdsmen, the girl brings her injured uncle to Strigan following an animal attack. She plays a local game called Tiktik with Breq. She reappears later in the city of Therrod, offering Breq assistance in a hostile environment.

Commanding the Justice of Toren during the occupation of Shis'urna, Rubran remains detached from the ideological struggles of her subordinates. Her political sympathies are opaque, frustrating superiors who attempt to gauge her loyalty during a brewing internal conflict.

Commanding the warship Mercy of Kalr, Vel represents the traditionalist, reactionary faction of the Radchaai military. She invites Seivarden to tea in hopes of courting an aristocratic ally who shares her distaste for recent progressive reforms. She actively dismisses Breq, refusing to extend basic social courtesies to someone she perceives as low-class.

Operating as the omnipresent artificial intelligence of the Omaugh Palace station, Station constantly monitors the physical responses and financial transactions of all inhabitants. It recognizes Breq as an anomalous foreigner and reports her irregular vital signs to security forces.

Functioning as the sentient warship under Vel's command, Mercy of Kalr shares a structural similarity to Breq's original form. The ship experiences confusing memory alterations regarding secret visits from its supreme commander, suggesting a developing consciousness.

As a wealthy member of the Tanmind ruling caste, Jen Shinnan resides in the upper city of Ors. She actively resents the citizenship granted to the lower-class Orsians and fabricates crimes to justify violence against them. She complains bitterly at dinner parties about the loss of her economic monopolies.

Foraging for tubers in a prohibited lake zone, Denz Ay discovers a hidden cache of pre-annexation weapons. Fearing a setup by the local elite, she bypasses standard channels to report the find directly to Awn. Her discovery sets off a chain of catastrophic political events.

Operating as a human soldier in the Seven Issa decade, he accompanies Skaaiat during the occupation. He openly expresses discomfort with the simulated emotions of ancillary units, representing the human military faction poised to replace the corpse soldiers.