Ellen is a dark-haired Jewish girl. Annemarie is a blond Lutheran. Ellen excels at dramatics while Annemarie is athletic, especially in running. Ellen is more timid than Annemarie. Ellen is an only child whereas Annemarie had two sisters. The girls live in the same apartment building but live on different floors. Ellen wears a necklace with a Star of David on it, but Annemarie doesn't have a necklace. Ellen has never seen the sea other than the harbor while her friend's uncle is a fisherman, so Annemarie gets to see the ocean quite frequently. Ellen is more of a city girl while Annemarie has visited and loved the countryside. Both girls are the same age, best friends, and attend the same school. They both were accosted by German soldiers on their way home from school while running along the sidewalk. Both will be in deep trouble in captured by the Germans; Ellen for her religion and Annemarie for her helping the Rosens escape. Both are Danish.
In Lois Lowry's novel Number the Stars, Annemarie Johansen and Ellen Rosen are best friends. They share many characteristics and differences as well. Both girls live in Denmark during World War II. They attend the same school and are both good students, though Annemarie claims that Ellen is a better student than she is. They are not biological sisters, but they pretend to be so that Ellen won't be captured by the Nazis. Ellen and her family are Jewish. Annemarie's family are Lutherans. The Johansens agree to hide Ellen when the Nazis announce they are taking all Danish Jews for relocation. Annemarie had a sister who died, so Ellen takes on her persona, telling Nazi soldiers her name is Lise. Ellen is an only child and her parents have left Denmark to escape the Nazis.
Ellen wears a necklace with the Star of David, which identifies her as a Jew. Annemarie doesn't wear anything around her neck.
Physically, the girls are quite different. Ellen has dark hair worn in pigtails. Annemarie's hair is a silvery blond and she wears it down. Annemarie is tall and lanky, whereas Ellen is shorter and stockier.