The title of Chapter nine is Leech, which refers to Chillingworth. In real life a leech is a creature that sucks humans’ blood. Chillingworth is like a leech in the sense that he is sucking information from Dimmesdale bit by bit. At first, Dimmesdale didn't accept Chillingworth's help, but afterwards he concluded that God must have sent Chillingworth to him to save him. In chapter nine, Chillingworth shows his devilish side when he and Dimmesdale live together in the widow's house. Some people think that it is best to let Chillingworth live with Dimmesdale for the sake of the reverend’s health, but others don't think that way. They see an ugly expression on Chillingworth’s face that makes them question Chillingworth’s intentions.
As the days pass, Chillingworth and Dimmesdale grow closer to each other. Dimmesdale reveals his secret nature.
In the beginning of chapter ten, Hawthorne describes Chillingworth in a positive way. "Old Roger Chillingworth, throughout life, had been calm in temperament, kindly, though not of warm affections, but ever, and in all his relations with the world, a pure and upright man."(117). But he nevertheless shows his evil side later in the chapter. Dimmesdale trusts him as his physician in the common, intimate way that patients trust their doctors. Chillingworth asks the reverend many harsh questions to find out if he is truly the sinner he suspects he is. One day when Dimmesdale is in a very deep sleep, Chillingworth sneaks into the room and sees his bare chest. This action apparently gives him everything he needs to know. He maintains his devilish nature, and continues his plan for revenge.