Primarily, it is the source off all that is negative in the novel - his class is the reason that Cathy takes Edgar's hand in marriage over his, her eternal lover ('If my brother had not brought Heathcliff so low I would not have thought of it' 'It would degrade me to marry Heathcliff now'). Furthermore, his change in social status during Cathy's first two years of marriage with Edgar presents further torment. Cathy now regrets her decision to marry Edgar - despite loving him, she now deems Heathcliff worthy of her hand, and she cares for Heathcliff more than she does Edgar. However, she refuses to leave Edgar, because she does love him, and says she could not bear to leave him. This breaks Heathcliff's heart, and embittens him towards Cathy and the Lintons, thus taking revenge in the form of his marriage to Miss Isabella Linton. This in turn breaks Cathy's heart, and this ultimately kills her. Heathcliff has his heart broken all over again, from grief and regret, and Edgar too is heartbroken to lose his beloved wife. For the rest of the novel, misery haunts every character in some form or another.