Marie-Laure LeBlanc The daughter of a Paris museum locksmith, Marie-Laure goes blind when she is 6 years old. Shortly after she turns 12, she and her father evacuate Paris and move to her great-uncle Etienne’s house in Saint-Malo. Her father is arrested, leaving behind a wooden model of Saint-Malo, which hides the Sea of Flames, a valuable diamond. She and Etienne eventually join the French resistance movement, using Etienne’s radio to broadcast Allied intelligence. During the siege of Saint-Malo, when she is 16, she is trapped in her attic for days while German officer von Rumpel searches Etienne’s house for the Sea of Flames. Marie-Laure begins broadcasting from Etienne’s radio and is heard by Werner, who locates the broadcast signal, goes to the house, and saves her from von Rumpel. After the war, Marie-Laure works at the museum where her father used to work. She has a daughter named Hélène and a grandson named Michel.
Werner Pfennig Werner and his sister, Jutta, grow up in an orphanage in Zollverein, Germany. Werner has a brilliant mind and wants to be a scientist, but he is told he will be sent to work in a coal mine when he is 15. When he impresses a Nazi official named Rudolf Siedler by repairing a radio, he receives a chance to avoid the coal mine by attending the National Political Institute of Education at Schulpforta. When Werner is 16, a teacher named Dr. Hauptmann tells the government that Werner is 18 so that Werner can be drafted into the military. Werner joins a unit responsible for locating and destroying anti-German radio broadcasts. His team is tasked with finding Etienne’s broadcast in Saint-Malo. They are caught in an Allies’ bombing and trapped underground for days. While underground, Werner hears Marie-Laure broadcasting. He escapes and goes to rescue her from von Rumpel. Later captured by the Allies as a prisoner of war, he becomes sick and delirious; he wanders into a minefield one night, sets off a mine, and dies.
Frank “the Giant” Volkheimer An older student at Schulpforta, 17 years old when Werner first meets him at the age of 14, Volkheimer is a legend among his fellow students, powerful and brutal. However, he is also a lover of classical music. He is one of Hauptmann’s pet students at Schulpforta and later leads the anti-radio task force that Werner joins. When he is trapped underground with Werner during the siege of Saint-Malo, Marie-Laure’s music on the radio inspires him to blast his way out of the death trap with a grenade.
Daniel LeBlanc Marie-Laure’s father. He is the locksmith at Paris’s Museum of Natural History until the German occupation, when he is entrusted with the Sea of Flames diamond. LeBlanc takes Marie-Laure to Etienne’s house in Saint-Malo, where he builds her a model of the city and hides the Sea of Flames inside it. He is arrested under suspicion of treason after the perfumer, Claude Levitte, sees him taking measurements for his model. Sent to a German prison camp, he occasionally writes letters to Marie-Laure until his death from influenza in 1943.
Jutta Pfennig Werner’s younger sister by two years. While in the orphanage, she uses the radio that Werner fixes to listen to foreign radio broadcasts, even after they are banned. Because of her access to foreign information, Jutta is suspicious of Nazi propaganda and doesn’t want Werner to go to Schulpforta. She writes letters to Werner throughout his time at Schulpforta and in the military. Later, she is raped by three Russian soldiers, whose army occupies part of Berlin after the war. As an adult, she becomes a math teacher in Essen, Germany.
Etienne LeBlanc Marie-Laure’s great-uncle. He and his brother, Henri (Marie-Laure’s grandfather), worked together as teenagers to create and broadcast the science radio programs that Werner and Jutta grew up listening to. The two brothers became signalmen in World War I (WWI), and Henri died during the war. As a result, Etienne is traumatized; he is too frightened to leave his house and sometimes imagines horrors that aren’t there. When Marie-Laure arrives, he often reads to her, and his love for her slowly makes him brave again. After his housekeeper, Madame Manec, dies, he and Marie-Laure use the radio transmitter, which he and Henri had set up as boys, to broadcast Allied intelligence for the French resistance movement.
Madame Manec Etienne’s housekeeper. Although old, she is brisk and energetic. Unwilling to sit by and let the Germans destroy her nation, she organizes a group of old women in Saint-Malo to work for the resistance. She arranges for Allied intelligence to be delivered to her in loaves of bread and broadcast with Etienne’s radio. Etienne refuses at first, but after Madame Manec dies of pneumonia, her plan becomes a reality.
Frederick Werner’s bunkmate and only friend at Schulpforta. The son of rich Berlin parents, he is a thin boy with pale skin and a passion for birds. Although he wears glasses, he pretended not to need them and memorized the eye charts in order to be admitted to Schulpforta. Because he isn’t as physically fit or as brutal as the other boys in Schulpforta, he is singled out for punishment, especially after he refuses to participate in killing an enemy prisoner. He is beaten so badly that he nearly dies and is sent home, his mind permanently damaged.
Reinhold von Rumpel A gemologist and a sergeant major in the Wehrmacht (German military). He has a wife and two daughters. In 1940, von Rumpel is 41 years old, has a distinctive limp, and quickly failing health as a result of lymphoid tumors in his throat and small intestine. He dedicates himself to finding the Sea of Flames diamond, which is rumored to make its owner immortal. After finding all three replicas of the diamond, his search leads him to Saint-Malo, where he enters Etienne’s house during the siege and spends days looking for the gem. He almost finds Marie-Laure in the house when Werner arrives and kills him.
Dr. Hauptmann Instructor of technical sciences at Schulpforta. After discovering Werner’s gift for mechanics, he makes the boy his special student, teaching him to calculate the location of radio broadcasts using trigonometry in order to locate and kill resistance fighters. In 1942, Hauptmann is transferred to Berlin, where he lies to the government about Werner’s age, telling them Werner is 18 instead of 16, so that the boy can be drafted into the Wehrmacht.
Frau Elena A kindhearted woman who runs the orphanage where Werner and Jutta grow up. A Protestant nun from Alsace, France, she teaches the Pfennigs to speak French as well as German.
Madame Ruelle The owner of Saint-Malo’s bakery and one of Madame Manec’s fellow resistance fighters, she bakes slips of paper with Allied intelligence into loaves of bread; Marie-Laure brings these loaves home to Etienne, who broadcasts the information on his radio.
Walter Bernd An engineer in Werner’s military unit and one of the men trapped with him beneath the hotel.
Dr. Geffard Daniel LeBlanc’s coworker at the museum, a specialist in mollusks and a friend to Marie-Laure.
Hans Schilzer A boy at Frau Elena’s orphanage who joins the Hitler Youth.
Herribert Pomsel A boy at Frau Elena’s orphanage who joins the Hitler Youth.
Claudia Förster A girl at Frau Elena’s orphanage who goes with Jutta and Frau Elena to Berlin, where they are raped by Russian soldiers.
Hannah and Susanne Gerlitz Twin girls at Frau Elena’s orphanage who go with Jutta and Frau Elena to Berlin, where they are raped by Russian soldiers.
Rudolf Siedler A Nazi official whose radio Werner fixes. He writes a letter recommending Werner to the Nazi school.
François Giannot The man to whom Daniel LeBlanc is supposed to deliver the Sea of Flames diamond. He flees to London when the Germans invade France.
Claude Levitte A perfumer in Saint-Malo and a Nazi informer. His information is responsible for the arrest of Marie-Laure’s father. He also directs von Rumpel to Etienne’s house.
Bastian The round-bellied commandant in charge of field exercises at Schulpforta. He is responsible for many of the horrors Werner sees at the Nazi school, including the brutal mistreatment of Frederick.
Helmut Rödel The boy at Schulpforta who first identifies Frederick as the weakest cadet during a field exercise. Prompted by Bastian, he beats Frederick.
Frau Schwartzenberger An old Jewish woman who lives in the same building as Frederick’s family.
Fanni Frederick’s family’s maid.
Dupont A lapidary hired by the Paris museum to make three replicas of the Sea of Flames diamond.
Madame Fontineau One of Madame Manec’s “Old Ladies’ Resistance Club.”
Madame Hébrard Saint-Malo’s postmistress and one of Madame Manec’s “Old Ladies’ Resistance Club.”
Madame Guiboux One of Madame Manec’s “Old Ladies’ Resistance Club.”
Madame Carré Saint-Malo’s florist and one of Madame Manec’s “Old Ladies’ Resistance Club.”
Madame Blanchard One of Madame Manec’s “Old Ladies’ Resistance Club.”
Hubert Bazin A French resistance fighter. He gives Marie-Laure the key to the grotto gate.
Neumann Two A corporal in Werner’s military unit. He is sent to the war front shortly before the bombing of Saint-Malo.
Neumann One The driver in Werner’s military unit. He is sent to the war front shortly before the bombing of Saint-Malo.
Jean Brignon A Nazi informant who calls von Rumpel with information about what happened to Daniel LeBlanc.
Albert Wette Jutta’s husband, a kind, slow-moving accountant.
Max Wette Jutta’s son, whose fondness for science and love of unanswerable questions reminds Jutta of Werner.
John A Canadian scientist and Marie-Laure’s second lover. He is the father of Marie-Laure’s daughter Hélène; he and Marie-Laure separate amicably once Marie-Laure becomes pregnant.
Hélène Marie-Laure’s daughter, 19 years old in 1974.
Michel Marie-Laure’s grandson, nearly 12 years old in 2014.