Felix Salinger
Felix Salinger is the main character and protagonist of Once. At the start of World War II, Felix's parents decided to drop him off at a Catholic orphanage at the age of six to keep him safe. Since he was dropped off at the orphanage, Felix has spent his days creating stories and daydreaming about his parent's return. He thinks his parents will return. However, readers know that his parents will never return. Although it is never explicitly stated, readers know that Felix's parents were killed in the Holocaust—likely in a concentration camp. This reflects Felix's naivete and shows how much he has to learn.
Even though Felix is only nine years old during the events of Once, he is remarkably mature. He is forced to endure a lack of food, violence, racism, and other unfortunate events due to Adolf Hitler and his Nazi party. For instance, most children wouldn't get excited when they got a single carrot. Felix did because he was used to not eating much.
Zelda
Zelda is another significant character in Once. About halfway through the book, Zelda's house starts ablaze with her inside it. Felix sees this and decides to rush into her house and save her. Felix carries her out of the burning house, and the two begin a friendship. They go through a lot together, including escaping death on several occasions. Zelda becomes Felix's emotional rock, and Felix becomes Zelda's. Although she is very young, Zelda is very mature and exceptionally innovative.
Barney
Barney is the man who saves Felix and Zelda from surefire death. Readers never discover if Barney is Jewish, but readers do know that Barney is a good man with a great heart who puts everything on the line to help two helpless people.
Barney is also a dentist and decides to give Felix work to do. He asks Felix to tell his patients exciting stories, many of whom are bored or in pain. Felix agrees and starts to help Barney, which enriches his and Barney's life too.
Adolf Hitler
Adolf Hitler is a secondary character in Once. He was the leader of the Nazi party and the Führer (essentially President) of Germany from 1933 to his death in 1945. It was Hitler, Felix discovers, that created the anti-Jewish policies in Nazi Germany. And it was Hitler who was likely responsible for the deaths of his parents and so many Jewish people in concentration camps like the one Zelda and Felix were going to. In many ways, Adolf Hitler is the epitome of evil because he was responsible for the cruel and senseless deaths of millions of people he didn't like.
