Death, the collector of souls, arrayed in any or all the world's colours when it comes, narrates the story of a young girl coming of age during the horrific times of Nazi Germany and World War II. To the reader, Death insists that it "most definitely can be cheerful", even affable, but also relates that it most certainly cannot be nice. And sometimes Death is "compelled" to take action in sympathy with the human story. Death sees the colours around him before he sees anything else. The story is told from his point of view, over the three times he sees the main character Liesel Meminger.
The protagonist of the story is an adopted girl on the verge of adolescence, with blonde hair. Her eyes, however, are brown. She is fostered by the Hubermanns after her biological father "abandons" their family due to being a Communist, her brother dies, and her mother is forced to send her to a foster home to avoid Nazi persecution. Liesel is the "book thief" referred to in the title because Liesel is fascinated by the power of words. Liesel stole books from a grave digger, a bonfire and the mayor's wife, Ilsa Herman.
Hans Hubermann (Papa)
Liesel's foster father and husband of Rosa, Hans is a former German soldier during the First World War, accordion player, and painter. He develops a close and loving relationship with Liesel, and becomes a main source of strength and support for her. He, like Liesel, doesn't have much experience with reading. Together, the two help each other with reading and write all the words they learn on a wall in the basement. He helps Max because Max's father saved Hans in the First World War.
Rosa Hubermann (Mama)
Rosa is Liesel's sharp-tongued foster mother. She has a "wardrobe" build and a displeased face, brown-grey tightly-cinched hair often tied up in a bun, and "chlorinated" eyes. Despite her temper, she is a loving wife to Hans and mother to Liesel. To supplement the household income, she does washing and ironing for five of the wealthier households in Molching. When she was introduced to Max the reader sees her soft side.
Liesel's neighbour, Rudy, has bony legs, blue eyes, lemon-coloured hair and a penchant for getting in the middle of situations when he shouldn't. Despite having the appearance of an archetypal German, he does not directly support the Nazis. As a member of a relatively poor household with six children, Rudy is habitually hungry. He is known throughout the neighbourhood because of the "Jesse Owens incident", in which he coloured himself black with charcoal one night and ran one hundred meters at the local sports field. He is academically and athletically gifted, which attracts the attention of Nazi Party officials, leading to an attempted recruitment. His lack of support for the Nazi party becomes problematic as the story progresses. Rudy becomes Liesel's best friend and later falls in love with her.
A Jewish fist-fighter who takes refuge from the Nazi regime in the Hubermann's basement. He is the son of a WWI German soldier who fought alongside Hans Hubermann, and the two developed a close friendship during the war. He has brown, feather-like hair and swampy brown eyes. During the Nazi reign of terror, Hans agrees to shelter Max and hide him from the Nazi party. During his stay at the Hubermanns' house, Max befriends Liesel, because of their shared affinity for words. He writes two books for her and presents her with a sketchbook that contains his life story, which helps Liesel to develop as a writer and reader, which, in turn, saves her life from the bombs falling on her. 
The wife of the mayor of Molching who employs Rosa Hubermann. She did fall into a depression state after the death of her only son in the Great War. Ilsa allows Liesel to visit, read and steal books in her personal library. She also gives Liesel a little black book, which leads Liesel to write her own story, "The Book Thief".
Liesel's little brother, who has unfortunately died suddenly on the train with his mother and sister, while being transported to their foster parents. His death is what allowed the first book to be stolen, a gravedigger's manual dropped by a young boy learning to work in the cemetery. He died by coughing blood, corroded brown in colour.
Paula Meminger (Liesel's Mother)
Liesel's mother is only mentioned in the story a few times. Liesel's father was taken away by the Nazis prior to the novel starting because he was a Communist, and the reason her mother – Paula Meminger - was taking both her children to foster care was to save them from Nazi persecution. For a while Liesel writes letters to her mother thinking there is a chance she is still alive. Like Liesel's father, Liesel's mother dies, but Liesel eventually realizes her mother gave her away to protect her.