The reader of The Boy in The Striped Pajamas meets Maria at the beginning of the story. As the maid or housekeeper, she is an important part of family life, so important that when the family move out of Berlin to"Out-With," Maria moves with them. When the "Fury" visits their home Maria is sure to bow her head "lower than usual, implying her inferiority. Maria defers even to "Master Bruno" and bows her head when she approaches him.
Bruno trusts Maria implicitly and sees her as "part of the family," seeking her opinion about the "awful" place they have moved to but Maria avoids his questions as it is seemingly not her place to comment. She is horrified and concerned for Bruno when he protests "Stupid Father." She tells Bruno how, due to a friendship between Bruno's grandmother and Maria's mother who was a dressmaker for Bruno's grandmother, Bruno's father had been very good to Maria and she will be eternally grateful for such kindness. She even muses about how he could do such terrible things now when he did such a kindness for her, although she does not voice her opinion.
She does tell Bruno what she knows about Pavel and how he was a doctor "in another life." She is clearly afraid of Bruno's father and also afraid of speaking out against the family or the Germans, for fear of being reprimanded and out of loyalty to Bruno's father. She is always cautious and even telling Bruno to be careful of what he says.
It is then implied that Maria is Jewish by her behavior and the fact that the family take her with them - out of a sense of duty on Bruno's father's part - because, left behind in Berlin as a Jew she would have been persecuted.