Cyril is a cynical, self-preserving con man serving as a Private First Class in the US 43rd Division's Company P. Having honed his manipulative skills as a riverboat cardsharp, he views survival as a rigged game and regularly uses deception to force other soldiers to take his place in dangerous assignments. He carries a deep-seated rejection of idealism and faith, deliberately distancing himself from the religious legacy of his estranged father.

The Angel is a luminous, supernatural woman found caught in the battlefield wire wearing a red dress and a blue cape. Initially appearing as a helpless victim of human conflict, she functions as an enigmatic mirror who reflects the deepest desires and unhealed traumas of the soldiers who rescue her. Her presence introduces a chaotic, ambiguous supernatural element into the brutal reality of the trenches.

Lewis is a fourteen-year-old orphan who lied about his age to enlist in the military, seeking adventure and a sense of family. He serves as a sharp contrast to the industrialized brutality of the war, clinging to romanticized dime novels and pulp adventures as a coping mechanism. His persistent innocence and desperate search for belonging steadily chip away at the emotional walls built by his older squadmates.

Reis is the youngest-ever commander of the 43rd Division, leading his men with a dangerously outdated philosophy of war that results in massive casualties. He actively conceals an underdeveloped right arm while overcompensating with a rigid, theatrical martial posture and a customized uniform. Driven by profound vanity and a desperate need for personal glory, he views the war primarily as a vehicle to secure a Medal of Honor.

Hugh is a large, slow-witted private marked physically by the trench environment, suffering from severe trench mouth and a gas-burned scalp. He operates on base impulses and a highly simplistic interpretation of masculinity, aspiring only to be seen as a formidable fighting man. His primary motivation is an obsessive, unrequited devotion to a woman back home, which makes him highly susceptible to manipulation.

Vincent is a conspicuously clean and highly nervous private who has earned a grim reputation as a battlefield scavenger. Derisively known as a vulture among his peers, he actively avoids direct combat while preferring to profit from the destruction by looting valuables from both Allied and German casualties. He approaches the war with an opportunistic, capitalist mindset devoid of moral boundaries.

Ben is a flamethrower operator and the lone Black soldier in Company P, recently transferred from a segregated infantry regiment. He suffers from severe shell shock that causes a constant physical tremor, yet he maintains a quiet dignity in the face of overt racial hostility from his white peers. He clings tightly to the belief that his transfer was a mark of personal validation from his commander.

Bernard is Cyril's late father, a clergyman whose intellectual struggles with faith ultimately alienated his congregation and his son. He perished aboard the RMS Lusitania while traveling to Europe as a minister, an act his son interprets as an escape from domestic failure. His lingering influence heavily shapes his son's cynical worldview.

Effie is a young woman living back in the United States who serves as the object of Hugh Popkin's intense, unrequited affection. Through her letters detailing civilian dates, she unknowingly fuels Popkin's desperate need to prove himself as a dominant fighting man in the European trenches.

Naomi is Ben Veck's daughter, who represents the innocent domestic life he left behind in a racially hostile America. She serves as the emotional anchor for Veck's endurance in the war and becomes the figure he superimposes onto the supernatural phenomena he encounters.

Father Muensterman is the chaplain for the American forces in the trenches. Overwhelmed by the grotesque realities of the battlefield, he struggles to maintain his composure and warns the soldiers that they will find only the devil out in No Man's Land.

"Frenchy" is an intoxicated French soldier who occupies an abandoned artillery piece in the ravaged forest. He holds deep contempt for the American forces, mocking their late entry into the conflict and challenging their understanding of the war's true devastation.