Robert is a 19-year-old Canadian officer who enlists in the military during the First World War. He comes from a wealthy, though emotionally distant, family in Ontario and holds a deep affection for animals and his sister Rowena. He begins his military career seeking purpose but quickly encounters the brutal, muddy realities of army training and overseas trench warfare. He acts as an observer to the destruction around him, maintaining a strong internal moral compass.

Rowena is Robert's sister, born with hydrocephalus, which confines her to a wheelchair. She shares a gentle, tender bond with Robert, who acts as her primary protector and builds hutches for her beloved pet rabbits. She remains separate from the cruelty of the outside world, anchoring Robert's understanding of compassion.

Juliet is a young girl from an aristocratic British family whose country estate, St. Aubyn’s, serves as a convalescent hospital. She observes the adults around her with a sharp, diary-keeping eye. She offers a child's perspective on the complex relationships and traumas of the soldiers passing through her home.

Robert's mother is a woman who struggles with severe depression and relies heavily on alcohol. She expresses her grief and anxiety through emotional distance, reacting to Robert's enlistment with sharp hostility rather than outward sorrow. Her inability to cope with loss creates a volatile home environment.

A famous varsity athlete and recognized war hero whom Robert encounters during training. He represents the traditional military ideal of toughness and skill, prompting Robert to view him as a potential mentor. His private life involves complex, rough encounters that challenge Robert's understanding of heroism.

Juliet's older sister is an aristocratic woman known for her striking beauty and fiercely competitive nature. She involves herself with various military officers, creating intense relationships with men who are often wounded or deeply affected by the conflict. She commands attention whenever she enters a room.

Robert's father is a successful business owner who manufactures tractors. He struggles to express his emotions verbally but attempts to support his children through practical gifts, such as a six-shooter pistol for Robert. He quietly endures his wife's deteriorating mental state.

A young officer who travels on the same transatlantic ship as Robert. He contracts a severe case of pneumonia during the voyage, prompting Robert to spend significant time caring for him. The two men develop a profound, quiet friendship based on mutual vulnerability.

A military captain who illustrates children's books and maintains a strong connection to nature. He rescues and cares for injured animals, including birds, hedgehogs, and a toad, amid the devastation of the front lines. He shares Robert's compassion for the innocent creatures caught in the war.

Robert's company commander at the front. He represents the bureaucratic and often irrational military leadership, issuing rigid orders that frequently ignore the practical realities and dangers of the battlefield. His decisions routinely put men and animals in unnecessary peril.

A junior officer who accompanies Robert at the front. He relies heavily on antiquated books about military strategy to make sense of the war, though these texts prove entirely inadequate for the reality of the trenches. He struggles profoundly with the psychological toll of the artillery bombardments.

A bugler who acts as Robert's dedicated assistant. He remains loyal and follows orders through treacherous conditions, providing practical support during terrible marches through the muddy, dangerous French landscape.

An officer sharing the dugout with Robert. He claims to be devoted to fragility and takes comfort in a stained-glass panel of St. Eloi, clinging to fragments of beauty amid the destruction. He proves willing to assist Robert in defiance of strict military orders.

Robert's younger brother. He remains mostly on the periphery of the family's central tragedies. He is tasked with watching over Rowena but cannot prevent the inevitable, serving as a contrast to Robert's intense feelings of responsibility.

A fellow recruit who trains with Robert in Alberta. He frequently sings, worries about his appearance in mirrors, and strains his relationship with Robert by borrowing money without returning it.

A nurse who treats military personnel at the Bois de Madeleine hospital. She views Robert as the absolute definition of a hero and provides historical commentary on his medical care and the silent agony he endured.

A large man hired by Mrs. Ross to kill Rowena's rabbits. When Robert attempts to intervene, Teddy physically overpowers him to complete the harsh task.

A German Jewish woman who runs the brothel near the military barracks in Alberta. She maintains a surprisingly sedate and orderly environment for the visiting recruits.

A red-haired girl working at Marie Dreyfuss's brothel. She attempts to initiate Robert into physical intimacy and tries to make casual conversation when he proves anxious and inexperienced.

A soldier under Robert's command during a dangerous crater mission. He helps maintain discipline among the men and faces a terrifying gas attack alongside Robert, struggling to survive in the chemical fog.

The mother of the d’Orsey children. She prioritizes her gardens and religion over high-society life, eventually turning the family’s country estate into a convalescent hospital for soldiers seeking refuge from the horrors of the army.

Juliet's older brother, considered one of the family geniuses. He associates with pacifist political circles and expresses deep, poetic sorrow about the legacy his generation will leave behind in the wake of the violence.

An officer at the front who shares dugout space with Robert, Devlin, and Rodwell. He participates in the fragile attempts to maintain normalcy and conversation amid the grueling trench warfare.

A severely burned officer whom Barbara d'Orsey visits in the hospital in London. He is entirely incapacitated and in agony, representing the terrible physical toll of the conflict on the young men.

A military officer tasked with pursuing soldiers who break protocol. He commands the unit that tracks down Robert after an incident with military property, relying on aggressive tactical force to end standoffs.