Heathcliff's faults, although largely accounted for by his depraved youth and his troublesome passion, outweigh the sympathy in Emily Brontë's Wuthering Heights . Throughout the story he commits numerous acts which could easily be deemed as evil. It is hard to forgive evil actions despite what motives lay behind them. Nelly affirms, “It is preferable to be hated than loved by him”.
Until he is sixteen, we are led to suspect him of nothing worse than a hot temper, a proud nature and a capacity for implacable hatred. Though Heathcliff possess inherently a savage violent nature, it is Catherine’s betrayal which leads to a steady deterioration in his character. The diabolic intensity with which Heathcliff pursues his revenge indeed, makes him seem a demon.
When Heathcliff returns to Wuthering Heights after several years, his frustration leads him to exact revenge on Hindley Earnshaw. He sets out deliberately to ruin Hindley, lending him money to gamble and drink and then getting him to mortgage the Heights to him so that he eventually becomes the master of the Heights. Hindley reduced Heathcliff to such a status that it would ruin Cathy to marry him. Heathcliff's villainy is shown when he returns the favour to Hindley, reducing him and his son Hareton to servant class. This is apparent when Heathcliff is talking to Nellie about his joy in degrading Hareton, he says, I've pleasure in him!..He has satisfied my expectations…”
His treatment of Hindley may still be morally justifiable, but nothing can excuse Heathcliff’s brutal treatment of innocent Isabella. He uses Isabella’s infatuation and gets her to elope with him. Isabella believes that Heathcliff is a kind decent man; however, soon after she marries him, he becomes abusive. This is also shown in a letter from Isabella to Nellie in which she says, “he is ingenious and unresting in seeking to gain my abhorrence! I assure you, a tiger, or a venomous serpent could not rouse terror in me equal to that which he awakens.”
His brutality is also shown in his last speech with his beloved Catherine. Instead of consoling her, he harshly treats her. Heathcliff says, 'Why did you betray your own heart, Cathy? I have not one word of comfort - you deserve this. You have killed yourself..They'll blight you - they'll damn you. You loved me - then what right did you to leave me?..I have not broken your heart - you have broken it - and in breaking it, you have broken mine.' This quote shows Heathcliff's anger, and his blaming of Cathy.
His desire for revenge however doesn’t end with the death of Hindley or with Isabella’s escape from the Heights. In his devilish scheme he pursues his revenge through Hareton, the son of Hindley, and Catherine the daughter of Edgar Linton. He treats Hareton as he had been treated by Hindley. Hareton is deprived of education, fumed into a mere farm land and treated as a servant.
His treatment of Catherine defies logic. He forgets that she is the daughter of his own beloved Catherine. He has imprisoned her till he can forcibly get Catherine married to Linton. Catherine is deliberately kept in the dark about Linton’s grave state of health. Heathcliff violently hits her when Catherine bites him in a bid to escape and he does not let her visit her dying father. Hareton and Catherine are innocent. They did no harm ro Heathcliff. To take revenge on innocents is really a brutish task and we cannot forgive him for this.
His treatment of his own sick son Linton is no better. He claims rights over his son Linton but has no love for the sickly boy. It is morally reprehensible that he terrorizes and mistreats even his own son. He forces him to woo Catherine, so that a marriage between them would make Heathcliff the master of Thrushcross Grange, after the death of his son. He is totally callous, unfeeling and cruel when he refuses to get a doctor for his dying son as he feels that his life is not worth a farthing. Even when Linton Heathcliff lets Catherine escape, he punishes the sick boy and makes sure Catherine is back at the Heights, immediately after the funeral of her father,
All these, indeed make him seem a demon and the readers are unwilling to draw any sympathy to him.