Misha is a small, young orphan surviving on the streets of Warsaw by stealing food. Initially lacking a name, background, or memories of his past, he calls himself "Stopthief" before an older boy gives him a fabricated history. He is highly naive about the realities of the war, admiring the invading soldiers' shiny boots and failing to understand the escalating danger around him. His swift running ability and small size make him an exceptionally skilled food smuggler.

Uri is an older, redheaded street boy who acts as a protector for the younger orphans in Warsaw. He provides Misha with a place to sleep in an abandoned barbershop basement and teaches him basic rules for survival. He possesses a strong sense of responsibility and relies on strict, occasionally physical discipline to keep Misha safe from the occupying soldiers.

Janina is a stubborn, initially sheltered young girl who strikes up an unlikely friendship with Misha. She leaves small trinkets on her front step in exchange for the bread he leaves for her. Prone to emotional outbursts and deeply attached to her family, she struggles to adjust when they are forced to leave their home, eventually mimicking Misha's dangerous smuggling habits.

Mr. Milgrom is Janina's father and a practicing pharmacist. He possesses a deep reservoir of empathy, continuing to fill prescriptions for those who cannot pay even after conditions deteriorate. Under extreme duress, he attempts to maintain religious traditions for his family, extending his paternal care to Misha without hesitation.

Mrs. Milgrom is Janina's mother, a woman who finds the transition to their new living conditions deeply traumatic. She withdraws emotionally from her surroundings and rejects Misha's presence in their space. She frequently mourns the loss of her former life, comfort, and humanity.

Uncle Shepsel is Janina's uncle, a cynical man who prioritizes his own survival above family loyalty. He frequently argues over small portions of food and openly resents Misha's inclusion in their household. He studies Lutheranism in a desperate bid to distance himself from his Jewish heritage and secure better treatment.

Kuba is one of the street boys who lives alongside Uri and Misha. Known as the "clown" of the group, he often instigates roughhousing and jokes to keep the others entertained in the face of poverty and danger.

Olek is a boy in the orphan group who lost one arm to a train accident. Despite the harsh realities of his life on the streets, he maintains a spiritual belief in angels, arguing with the other boys about their existence and protective abilities.

Enos is a grim-faced boy in the orphan group. He is highly skeptical and openly disbelieves in comforting concepts like angels, mothers, and even oranges, reflecting the deep cynicism born from his environment.

Big Henryk is a large, mentally disabled boy who refuses to wear proper shoes, preferring to cover his feet in bank coin bags. He throws loud tantrums when forced to wear normal footwear but follows Uri's commands when disciplined.

Jon is a quiet, sickly boy whom Misha describes as looking "gray." He speaks very little and struggles with persistent illness while living on the streets with the other orphans.

Doctor Korczak is a kindly physician who runs an orphanage in the city. Based on a real historical figure, he maintains order and cleanliness among his charges, teaching them songs and accepting the smuggled food that Misha brings to help keep the children fed.

Himmler is a high-ranking military official responsible for the area's occupation. He presents an ordinary, unremarkable appearance with thick glasses and a mustache, which shatters Misha's idealized perception of the occupying soldiers.

Buffo is a brutal ghetto police officer known for chewing mint leaves. The scent of mint acts as a warning for the street children, who fear his violent methods of punishment. He holds a particular hatred for Misha due to the boy's constant taunting.

Elzbieta is a farmer's wife who lives in the countryside. She provides food, water, and medical care to Misha, offering him a temporary reprieve from his wandering.

Vivian is a woman who encounters Jack (Misha) on a street corner in America. She brings him hot chestnuts and listens intently to his extensive stories about his past in Warsaw.

Katherine is a twenty-five-year-old woman with dark brown hair who seeks out Jack (Misha) in the contemporary timeline. She connects with him after a long search and introduces him to her young daughter, providing him with a sense of family.

Wendy Janina is a four-year-old girl in the contemporary timeline. She affectionately calls Jack "Poppynoodle" and provides him with a deep sense of peace, belonging, and joy.