Roger Chillingworth is the antagonist of the novel. As soon as he encounters Hester and learns that she has given birth to a child fathered by another man, he becomes obsessed with thwarting her plan to keep the identity of that man a secret. As Chillingworth explains, “I shall seek this man, as I have sought truth in books.” His motivation seems to be mainly jealousy, because he knows Hester never loved or desired him, and he wants to see what type of man she was attracted to. Interestingly, he makes it clear that he does not want to bring her lover forward for legal punishment or to enact violence against him: “Think not that I shall interfere with Heaven’s own method of retribution.” In keeping with his identity as a scholar, Chillingworth seems to want the knowledge for its own sake. As the plot progresses, and he confirms that Dimmesdale is the father of Hester’s child, Chillingworth becomes more obsessed with tormenting the minister. He generally acts independently, but when he learns of the plan for Hester and Dimmesdale to run away together, Chillingworth reacts by securing passage on board the same ship.

Chillingworth remains fairly constant over the course of the novel. At the beginning, he is a cold and calculating man who is good at keeping secrets and patiently biding his time. His character is slightly changed by the time he spends tormenting Dimmesdale because the more he tortures the minister, the more he becomes obsessed with continuing the torment, despite the pain it is causing. Chillingworth seems more invested in destroying Dimmesdale than finding any happiness for himself. When Hester confronts him and asks him to leave Dimmesdale alone, Chillingworth replies that “It is our fate. Let the black flower blossom where it may.” When Dimmesdale publicly confesses his sin, Chillingworth knows he is defeated, and he quickly changes, becoming a broken man, “with a blank, dull countenance out of which life seems to have departed.” Chillingworth’s actions change Dimmesdale and Hester because he prevents them from moving on, and keeps them fixated on the past. In his final words, Dimmesdale explains that he thinks Chillingworth was actually an agent of God’s mercy because he prevented the minister from running away from his secret, and forced him to atone.