Pavel and Maria are both servants in the household of Bruno's family; Maria travels with them from their original home, while Pavel is assigned to them from the concentration camp. Pavel used to be a doctor, but was stripped of his social status and wealth when the Nazis invaded, and sent to work alongside other Jews in the camp. He now works as a waiter and does not speak of his former stature. Maria is a maid and is friendly with Bruno; while he is of a higher social class, he treats her -- and Pavel -- with childlike deference, as they are adults. Maria is able to translate some of the adult ideas that Bruno experiences into ideas that he can understand, as when they discuss Pavel:
"He said he was a doctor," said Bruno. "Which didn't seem right at all. He's not a doctor, is he?"
"No," said Maria, shaking her head. "No, he's not a doctor.
"But he was. In another life. Before he came here."
Bruno frowned and thought about it. "I don't understand," he said.
"Few of us do," said Maria.
(Boyne, The Boy in the Striped Pyjamas, Google Books)
Pavel and Maria do not share any major scenes, but it is indicated that Maria understands how Pavel is unjustly punished for the crime of being Jewish. Maria is also the one who cleans up after Pavel is beaten to death by Lt. Kotler; she is unable to save him, but she saves Bruno from the emotional pain of seeing Pavel dead and bleeding. The connection between them is mainly of the working class, with Maria accepted as a normal part of society and Pavel indicted as a slave for his heritage.