A Dutch psychiatrist in the 20th-century narrative, Kristof transitions from a detached observer to an active participant in the French Resistance during Nazi-occupied Paris.

A precocious 12-year-old during the Nazi occupation, Sasha uses her intellect and inner strength to navigate her traumatic experiences and becomes an essential part of the underground community.

A responsible quarrier in the 17th-century timeline, Étienne evolves through his relationship with Alouette, seeking a life beyond survival and carving stone larks as personal expressions.

A charismatic Basque architecture student and mentor in the French Resistance, Alesander uses his knowledge of the Paris souterrain to aid escape efforts during the Nazi occupation.

Alouette’s mother, viewed initially as a cautionary tale of oppression, who later emerges as a complex survivor offering key insights to her daughter.

Polish Jewish refugees in Paris during the 1940s, they represent warmth and resilience, providing a grounding found family for Kristof amidst the looming threat of the Holocaust.

Characters like Claude Gobelin in the 17th-century and Dr. Blaise Claudel in the 20th-century represent oppressive systems, embodying commerce and medical control respectively.