Heathcliff is rescued by Mr. Earnshaw (father of Catherine and Hindley) from Liverpool, and taken to Wuthering Heights. As a child he frequently verbally and physically fights with Hindley, but is very close to Catherine. He and Catherine are caught whilst spying on the Linton children; she is cared for by them for a period of time, but he is left at Wuthering Heights with Hindley. When Catherine returns, she has been influenced by the Lintons and struggles to balance her desire to be like them and her friendship with Heathcliff. Heathcliff feels neglected by Catherine and cannot understand her friendship with the Linton children. After overhearing Catherine insulting him, Heathcliff leaves - and only returns after Catherine has married Edgar Linton. He is devastated by Catherine's death, and is haunted by her ghost until he himself dies. He forces his son, Linton, to marry Catherine and Edgar's protected daughter, Cathy (who he kidnaps) in order to punish Edgar.

Hareton:

Hareton is the son of Hindley Earnshaw and his wife Frances, who dies shortly after Hareton's birth. Hindley neglects and abuses him after Frances' death, and he is deprived of education. After Hindley's death, Heathcliff neglects Hareton, treating him as badly as he had been treated himself. Hareton remains ignorant and uneducated, and sees Heathcliff as a father despite his cruel treatment of him. After Cathy is kidnapped and taken to Wuthering Heights, they first argue, but later form an alliance after Cathy decides to teach Hareton to read. At the end of 'Wuthering Heights', Hareton is able to read and is engaged to Cathy.

- Cathy is in love with Heathcliff and she recognises the characteristics they share - "He's more myself than I am. Whatever our souls are made of, his and mine are the same." - The Lintons see Heathcliff as a "vulgar young ruffian" and "worse than a brute" which initially influences Catherine's behaviour towards him

- Nelly initially dislikes Heathcliff, but she offers him advice when Catherine first becomes close to Edgar Linton and occasionally appears to sympathise with him. However, by the end of the novel (and particularly after his treatment of Cathy and Linton) she views him as dangerous, cruel and beyond redemption

HARETON:

- Ellen is very close to Hareton as a young child, as she looks after him following the death of his mother - "I've no doubt he has completely forgotten all about Ellen Dean, and that he was ever more than all the world to her, and she to him." - When Cathy first meets Hareton as a child, she is shocked at the idea of him as her cousin - "She stopped and wept outright; upset at the bare notion of a relationship with such a clown." - Heathcliff treats Hareton badly to seek repayment for the way he was treated by Hareton's father - "He'll never be able to emerge from his bathos of coarseness and ignorance... he takes pride in his ignorance... first-rate qualities, and they are lost."

Stephanie Rogers says ''It may be assumed that Hareton, because he emulates him in many ways, fosters hatred for Heathcliff, his tormenter.  After all, Heathcliff did just that; he resented Hindley to such an extent that he planned and carried out revenge against him.  But Hareton does not hate Heathcliff.  Quite the contrary, he adores him.  Heathcliff is “the one friend he has in the world” (Brontë 193).  Likewise, Heathcliff says that he “covets” Hareton “twenty times a day,” “despite his degredation” (Brontë 192).  He says that “[he’d] have loved the lad had he been someone else,” that is, not the son of his enemy (Brontë 192).  This admiration reflects the deep, mutual respect between Hareton and Heathcliff.  Heathcliff wishes he were his son, and Hareton is proud to be his protégé, or, on a literary level, his double.  However, Hareton is not as aggressive as Heathcliff.

The real similarity is the importance of the 'nurture' of their character though, both Heathcliff - who was raised as a brute by Hindley ( deprived of education, separated from the one he loved, and forced to work as a labourer ) and Hareton - raised as a brute by Heathcliff to punish Hindley from the grave are brought up without civility in the name of revenge. "That one tree would grow as crooked as another with the same wind to twist it".

This draws a parallel between the two generations and shows how cruel Heathcliff really is to inflict the punishment of Hareton when in reality he is a capable and powerful man held back by a lack of education. Its captured perfectly in a quote by Heathcliff which says, 'who is one is gold put to the use of paving- stones, and the other is tin polished to ape a service of silver. MINE has nothing valuable about it; yet I shall have the merit of making it go as far as such poor stuff can go. HIS had first-rate qualities, and they are lost: rendered worse than unavailing'

Both characters are physically powerful and violent, Hareton often cursing and "takes pride in his brutishness" and Heathcliff when he was a similar age being ragged and dirty. The fact theres such a clear similarity shows not only how Hareton would unknowingly see the world through Heathcliff's eyes; but more importantly that Heathcliff knows the pain Hareton will be suffering and allows it. Reinforcing how dangerous revenge is and that Heathcliff will stop at nothing to take a twisted path of revenge.

The simple difference of personality is clear between the two characters, Nelly remarks "his honest, warm, and intelligent nature shook off rapidly the clouds of ignorance and degradation in which it had been bred (268)." These are inborn traits that seem absent in Heathcliff personalities. 

Because of these clear differences, it could be argued the clear purpose of the generations overlap is to show where Heathcliff's passionate love for catherine was destroyed and failed because of his ill nature. Hareton, with his true strength of character succeeded in his marriage of Cathy because it was for the right reasons, He almost inherited his true legacy which is of noble blood. Where Heathcliff failed because in reality he was 'That of a cuckoo's'.

Another linking theme is the love both Heathcliff and Hareton have for the 2 generations of Catherines, and the importance of the foundations of love. Its argued that because Heathcliff and Catherine's love is rooted in a 'soulmate' like childhood passion it will be everlasting, and therefore unforgiving. Whereas because Hareton's and Cathy's love is allowed to grow and develop freely its natural, the only love with flourishes without a 'curse'.

Furthermore, one of the most important themes is that of 'doubles', Hareton in a way is almost Heathcliff's evolution, a symbol of how he should have overcome his oppression and achieved his potential and why he succeeds when Heathcliff doesn't.

''The uncivil little thing [Cathy] stood on tiptoe, and whispered a sentence in Heathcliff's ear. He laughed; Hareton darkened: I perceived he was very sensitive to suspected slights, and had obviously a dim notion of his inferiority." (c21)  Heathcliff is cruel to Hareton and persistently reminds him that he is below  them.

Hareton possesses looks similar to Cathy (sr) and this may contribute to why Heathcliff wants to humiliate and degrade him so regularly. ''By the fire stood a ruffianly child, strong in limb and dirty in garb, with a look of Catherine in his eyes and about his mouth.''

''one is gold put to the use of paving stones, and the other is tin polished to ape a service of silver''  Heathcliff here compares his son Linton, to Hareton.