A Changer – a member of a near-extinct humanoid species capable of altering their physical appearance to perfectly mimic others. Working as an agent for the Idirans in their war against the Culture, Horza is driven by a deep philosophical opposition to machine-led civilisation, believing the Culture's AI Minds represent a fundamental threat to biological life.

The oldest member of Kraiklyn's Free Company, Aviger is a cautious, somewhat anxious mercenary who often voices the crew's collective nervousness. He serves loyally through the mission to Schar's World but is killed by Xoxarle when the Idiran breaks free.

A small, plump member of Kraiklyn's Free Company and a devout follower of the Circle of Flame religion. Kind-hearted and prone to prayer, she is killed during the firefight with the Idirans at station six in the Command System.

A Culture Sentient captured during the war. An analytical mind caught up in events far beyond her control.

Captain of the Clear Air Turbulence, a ragtag free-company mercenary ship operating on the fringes of the Idiran-Culture war. Vain and self-serving, not nearly as competent as he believes himself to be.

An aggressive, hot-tempered member of Kraiklyn's Free Company with small horn grafts on his head. Lamm is belligerent and dangerous, constantly cursing and threatening his crewmates. He dies on the Megaship Olmedreca after detonating a nuclear weapon during the iceberg collision.

A small, quiet crew member of the CAT who is prone to heavy drinking. After the disastrous Temple of Light raid, he refuses to use laser weapons, preferring projectile arms. He is killed during the firefight at station six in the Command System.

A Culture Special Circumstances agent tasked with pursuing Horza. Resourceful and formidable, but quietly conflicted about the moral cost of the war she fights in and the methods her side employs.

A Culture drone stranded among the mercenary crew of the Clear Air Turbulence. Fastidious, irritable, and constantly affronted by the company it is forced to keep.

The stocky, capable engineer of the Clear Air Turbulence. Good-natured and practical, Wubslin maintains the ageing ship through its many ordeals. He dies heroically in the Command System, staying at the train controls to try to move it out of the path of an oncoming collision.

A Querl (spy-father and warrior priest) of the Idiran Four Souls tributory sect, Xoralundra is Horza's long-time Idiran handler. An old, shrewd warrior with a dry wit, he rescues Horza from Sorpen and assigns him the mission to retrieve the Mind from Schar's World.

An Idiran Section Leader and warrior who infiltrates the Command System tunnels with a small force to capture the Mind. Cunning, manipulative, and immensely powerful, Xoxarle is captured by Horza's group but breaks free during the climactic battle, killing several crew members before being destroyed by Balveda.

A crew member aboard the Clear Air Turbulence and Horza's closest ally on the ship. Tough, pragmatic, and one of the few crew members Horza genuinely trusts.

A Mondlidician member of Kraiklyn's Free Company with a scar-marked face and an air of bored sophistication. He leaves the Company at Vavatch to join Ghalssel's Raiders and survives the war.

An ancient Culture drone that serves as Fal 'Ngeestra's companion and minder. It has an unusually deep voice and lacks the modern aura fields of newer drones, preferring to express itself vocally. It secretly records Fal's laughter.

A member of Kraiklyn's Free Company who pilots the shuttle during the Megaship operation. Wounded by Lamm's laser fire, he manages to rescue Horza but refuses to return for the others. He dies when the shuttle crashes into the Circlesea.

An Idiran warrior who accompanies Xoxarle into the Command System tunnels on Schar's World. Badly wounded in the firefight at station six, he manages to start a train that crashes catastrophically into station seven, killing himself and Wubslin.