One of the saddest aspects of Kafka's "The Metamorphosis," is the fact that Gregor Samsa genuinely cares about his family. From the opening of the story, he is shown to be a person who works hard to support his family, even though they do little for themselves. When Gregor morphs into a cockroach, however, the limits of familial loyalty and empathy are tested. Gregor is rejected from the family and Kafka seems to be making the point that there is no such thing as unconditional love. While there are multiple themes displayed in Kafka's text, the relationship between Gregor Samsa and his younger sister, Grete, is perhaps one of the principle themes in this short story. Once a close and loving relationship between Gregor and his sister, their bond slowly erodes over time as she grows older and the family matters continually worsen on account of Gregor's metamorphosed appearance.
In the beginning of the story, Grete is the only one of the family members that makes an attempt to care for Gregor and seemingly to pity her brother's condition. Gregor's mother is shocked by his appearance, she cannot bear to see him, and his father is hostile and violent towards his son. Although still fearful of his new insect form, Grete still shows genuine affection for Gregor and on her own makes the decision to care of him consequently making her the only one to face Gregor on a daily basis. She feeds him and takes in consideration what Gregor's new appetite prefers. Grete serves as the only link between Gregor and the mother and father. Gregor is very grateful for his sister's intricate care and he feels quite comfortable as an insect with high hopes that everything will return back to normal.
However, signs of change in Grete's demeanor and behavior toward Gregor are seen towards the end of the story. Grete undoubtedly begins to forget that this insect is her brother and that he still expresses human feelings and desires.