During Hester's interview with Roger Chillingworth of Chapter IV in The Scarlet Letter, Hester is extremely anxious about her old husband as she examines his face,
"Why doest thou smile so at me?" inquired Hester, troubled at the expression of his eyes. "Art thou like the Black Man that haunts the forest round about us? Hast thou enticed me into a bond that will prove the ruin of my soul?"
"Not thy soul," he answered, with another smile. "No, not thine!"
Thus Hawthorne has foreshadowed the reaction that the physician has when, as Dimmesdale sleeps, he moves the clothing that has always covered the minister's chest. As he stamps his foot on the floor in his Satanic delight, Chillingworth acts as Satan
comports himself when a precious human soul is lost to heaven, and won into his kingdom.
Now, Chillingworth does, indeed, possess the soul of the minister since he knows the secret sin that lies within Dimmesdale. This knowlege changes unalterably the relationship of the physician and his patient. For, Chillingworth becomes the fiend that holds the secrets of Dimmesdale's soul, and he can manipulate and torture the minister now. In Chapter XI, Hawthorne writes,
...the intercourse between the clergyman and the physician, though externally the same, was really of another character than it had previously been. The intellect of Roger Chillingworth had now a sufficiently plain path before it.....Calm, gentle, passionless, as he appeared, there was yet, we fear, a quiet depth of malice, hitherto latent, but active now, in this unfortunate old man, which led him to imagine a more intimate revenge than any mortal had ever wreaked upon an enemy.
Like Satan, Chillingworth intends evil for the man who has provided him with the revelation he has sought. As he has previously told Hester, "he will be mine," the physician makes plans for torturing the minister and avenging himself as the cuckolded husband upon Dimmesdale. Thus, Chillingworth becomes Dimmesdale's most deadly enemy.