Roger Chillingworth is the antagonist of the novel The Scarlet Letter by Nathaniel Hawthorne. He was the husband of Hester Prynne, who cheated on him and had a child while he was away for a very long time due to being kidnapped by Indians, and as punishment is permanently ostracized by the rest of the town and made to wear a large red letter “A” on her chest for the rest of her life, representing Adultery. Roger Chillingworth returns to the village just as the public shaming ceremony is happening, and he vows to find out the identity of the father and ruin his life even more than Hester’s.
Chillingworth becomes the town physician and receives a patient named Arthur Dimmesdale, who he realizes is feeling depressed and guilty because he was the one Hester had sex with, and with this discovery begins trying to emotionally torment Dimmesdale over long periods of time, so as to make him feel guilty and miserable as possible and destroy his soul. Chillingworth eventually becomes so obsessed with tormenting Dimmesdale that he starts physically becoming uglier and more demonic-looking, and soon he is completely consumed by his hatred and wrath.
When Hester realizes what her ex-husband is doing, she tells Dimmesdale and they plan to leave the country together to escape him, but when Chillingworth finds out about this he thwarts this plan by buying himself a ticket for the same ship. Eventually, the guilt-ridden Dimmesdale publicly confesses to everyone, causing him to suddenly die of a heart attack but redeeming his soul. This ruins Chillingworth’s plans to make Dimmesdale completely miserable forever and leaves him with nothing to live for; he dies within a year, but as a final act of goodwill with his soul no longer consumed by hate, he leaves all his money to Hester and her daughter Pearl. Of course, he also might have done this just to prove himself better than Dimmesdale.