In Emily Bronte's "Wuthering Heights", Heathcliff is adopted by the Earnshaw family and raised alongside their biological son, Hindley. Despite being treated as a member of the family, Heathcliff is often subject to abuse and discrimination because of his lower social status and mysterious origins.
His origin plays a crucial role in the novel as it sets the foundation for the intense class conflict and social tension that pervades throughout the story. Heathcliff's lack of a clear background makes him an outsider in the eyes of the other characters, and he is constantly aware of his inferior position in society. This drives his desire for power and revenge against those who have wronged him, and shapes his relationships with other characters such as Catherine and Hindley.
Furthermore, the uncertainty surrounding Heathcliff's background adds to the novel's eerie and gothic atmosphere, contributing to the sense of mystery and danger that surrounds him.
In conclusion, Heathcliff's adopted status and the mystery surrounding his origin are integral elements of the novel "Wuthering Heights". They serve to establish the class conflicts and social tensions that drive the characters' relationships and actions, as well as adding to the novel's atmospheric elements.