What does Chillingworth plan to do? Why?

Chillingworth, having figured out that Mr. Dimmesdale is the true father of Pearl, goes on a subtle campaign to hurt the minister as much as possible. Revenge consumes him to the point that he can only focus on causing the other man pain. Dimmesdale never figures out that his strongest enemy is the man whom he considers his only friend and physician. Really, beyond any sense of revenge, this guy becomes evil. His vengeance owns him and twists his soul.