Charlotte, a skilled pilot and engineer, is known for her resilience and intelligence. As an investigator of the silo system, she grapples with her insecurities while striving for independence.

Donald is an intellectual and cunning individual whose health deteriorates due to his internal struggle. His character primarily revolves around his efforts to atone for his past decisions regarding the silo's existence.

Lukas serves as a supportive figure and love interest to Juliette, noted for his emotional intelligence and curiosity. He provides stability and contrast in the narrative through his love for the stars and pursuit of knowledge.

Elise, a seven-year-old survivor, is characterized by her innocence, curiosity, and love of animals. She represents hope and a fresh perspective amidst the more jaded adult survivors around her.

Jimmy, an emotionally stunted survivor from Silo 17, becomes fiercely loyal and protective of those he loves. His journey involves growing into a confident leader figure for his community.

Paul Thurman, a former US senator, acts as the primary antagonist, characterized by his ruthless and eugenicist ideology. He is the mastermind behind the silo system and commands a repressive regime within Silo 1.

Darcy, initially a security officer in Silo 1, evolves into a resistance fighter seeking truth within the silo system. Known for his intelligence and deductive reasoning, he aids in the struggle against oppressive leadership.