A Culture citizen living in self-imposed isolation aboard the GSV Sleeper Service, nursing a decades-old grief. Her unresolved history with Genar-Hofoen becomes central to the events surrounding the Excession.

A General Systems Vehicle – one of the Culture's vast starships, home to billions. The Sleeper Service has been behaving eccentrically for decades, withdrawing from Culture society and filling its bays with tableaux of historical scenes. Its true motives are unknown.

A Culture ship with a notorious reputation. Unlike other Minds, the Grey Area reads the thoughts of biological sentients without consent – an act considered deeply transgressive in Culture society. Shunned by other ships, it answers only to the name its peers use as an insult.

The AI Mind that runs the Culture Orbital Masaq'. Ancient, thoughtful, and burdened by its own role in the long-ago war that set current events in motion. A gracious host with eight hundred years of guilt.

A Culture warship of the Abominator class – designed and built for pure destruction. Arguably deranged by any civilised standard, it is nonetheless extraordinarily effective. Assigned to assist Lededje, though its definition of assistance can be alarming.

A Culture ship whose full name is considerably longer than anyone cares to use. Fast, capable, and deeply invested in the unfolding crisis around the Gzilt Subliming, it serves as Cossont's primary ally and transport.

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 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.

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

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 Special Circumstances officer who recruited Zakalwe and manages his operations. Sharp, empathetic, and more personally invested in her agent than professional detachment would advise.

Diziet Sma's personal drone. Highly capable, drily witty, and possessed of a protective streak that once manifested in spectacular and bloody violence on Sma's behalf.

A Culture agent from the Quietus division, which deals with the afterlives and digital heavens and hells maintained by various civilisations. Sent to investigate the escalating war in the virtual realms.

A man who has lived for nearly ten thousand years, one of the oldest humans in the galaxy. He may hold the key to a secret about the Gzilt civilisation's founding that powerful people would prefer to keep buried.