Theo is a 50-year-old professor of Victorian Studies at Oxford University. Following the accidental death of his infant daughter and the onset of the global infertility epidemic, he lives an emotionally detached life and actively avoids taking responsibility for others. He acts primarily as an observer of the decaying world until a dissident group asks him to use his connections to the government on their behalf.

Xan is the Warden of England, an autocratic leader who governs the country alongside a five-member Council. A charming and pragmatic man who hates boredom, he relies on strict, brutal policies—including forced penal colonies and state-sponsored suicides—to maintain order. He values absolute control and demands unquestioning loyalty from his subordinates.

Julian is a member of the Five Fishes, an underground resistance group demanding democratic reforms and an end to state cruelty. Deeply religious, she operates with a quiet but firm conviction that her actions align with God's will. She refuses to accept the widespread despair of the infertile world and actively works to change the status quo.

Rolf is Julian's unsmiling husband and the leader of the Five Fishes dissident group. He actively campaigns against the Warden's regime, demanding elections and better treatment for immigrants and prisoners. Despite his activist rhetoric, he is deeply ambitious and primarily interested in acquiring political influence for himself.

Miriam is a middle-aged Black midwife and a dedicated member of the Five Fishes resistance group. Her involvement in anti-government activism is deeply personal, stemming from the state's brutal treatment of her brother. She brings practical medical knowledge to the dissident group.

Luke is a tall, melancholy priest without a parish who operates as part of the Five Fishes. He offers a quiet, spiritual presence within the dissident group as they organize against the Warden's government and evade the secret police.

Gascoigne is a short, innocent-seeming member of the Five Fishes. He takes on physical risks for the group's political demands, actively participating in their plans to disrupt government ceremonies.

Helena is Theo's ex-wife. She ended their marriage after struggling to cope with the death of their infant daughter, ultimately leaving Theo for an artist. She attempts to build a new, happier life free from Theo's emotional detachment.

Jasper is Theo's former history teacher and mentor. He views the infertility epidemic with cynical detachment, arguing that the end of humanity brings a welcome end to the irritating noise and culture of the youth. He considers moving in with Theo due to the government's centralization plans.

Hilda is Jasper's elderly wife. She participates in the Quietus, the government's formal ceremony for ending the lives of older citizens, an event that deeply impacts those who witness it.

Inglebach is a key member of the Council of Five. Considered the most sinister and intellectual figure in the group, he justifies the state's harsh policies by pointing out that England remains more stable than the rest of the world.

Felicia is a caustic, almost-beautiful woman who serves on Xan's ruling Council. She actively defends the administration's controversial programs, dismissing incidents of state violence as mere management issues rather than systemic failures.

Harriet functions as the wise elder woman of the Council. She supports the regime by arguing that freedom from fear is the most important right a government can provide, thereby justifying their extreme measures.

Martin is the Council member closest to Xan personally. Theo remembers always liking him, though Martin now uses his position to enforce strict limits on immigration and protect the state's resources.

Rawlings is an officer for the Secret Service Police (SSP). He visits Theo to investigate dissident activities, using his authority to gently mock Theo and create an atmosphere of manufactured fear.

Cathcart is an SSP officer and a member of the Omega generation, the youngest demographic alive. He assists his partner in policing the state and investigating political enemies.