In chapter XIV of Nathaniel Hawthorne's The Scarlet Letter, Hester and Chillingworth have their first conversation face to face nearly seven years after they first spoke to each other during Hester's stay in prison for adultery.
Many things are confessed during this conversation. Namely, Hester admits her hatred for Chillingworth and basically curses the day she married him. On the other hand, Chillingworth bitterly remembers his marriage to Hester as a huge abomination of which he should have anticipated this ending. After all, at the time they marry Hester is still a very young girl and Chillingworth is a middle age man.
Nevertheless, Chillingworth admits that he is aware of his obvious changes in physique. He also accepts that his changes are a result of anger and hatred, which have turned him into a form of fiend-because of Hester.
In a word, old Roger Chillingworth was a striking evidence of man's faculty of transforming himself into a devil, if he will only, for a reasonable space of time, undertake a devil's office. This unhappy person had effected such a transformation by devoting himself, for seven years, to the constant analysis of a heart full of torture, and deriving his enjoyment thence, and adding fuel to those fiery tortures which he analysed and gloated over.
However, Hester has her say as well. She actually looks at Chillingworth and confesses her dread
What see you in my face,” asked the physician, “that you look at it so earnestly?”
“Something that would make me weep, if there were any tears bitter enough for it,” answered she. “But let it pass! It is of yonder miserable man that I would speak.”
Conclusively, chapter XIV openly and descriptively narrates that Roger Chillingworth has, indeed, transformed from bad to worse, all because of his obsession in making both Dimmesdale and Hester pay for what he feels is a personal offence to himself.