"Chillingworth, in his connection with the scarlet letter, is the worst of the Puritan community. He is always identified as the devil or the devil's emissary (126), as an 'archfiend' (151). Pearl, who sees through everyone, is the first to associate him with Satan. And by the time of Hester's last private interview with him, just before she reveals his identity to Dimmesdale, she also sees him as a satanic figure in the form of a bat (169).
[. . .]
Chillingworth's evil character-like something right out of melodrama -- is also reflected in his physical appearance. As his human faculties become more and more out of balance -- his intellect becoming overdeveloped at the expense of his heart -- one side of his body becomes out of balance with the other. Even when he married Hester, this man of the study and laboratory already had a humped back. His deformity of body finally represents a deformity of character in which heart and soul play little part. As a result, he becomes at last bent over toward the ground, more like a snake than a human being. The contrast here is with Pearl, who, while she is thought by some in the community to be the child of Satan, is still strikingly beautiful, a perfect physical specimen.
In one aspect of human nature, however, Chillingworth is like no other. While not sharing in the full range of human warmth and emotions encompassed by the 'A,' he becomes monomaniacally supreme in one aspect alone, sacrificing all things good, even his own life and health, for that diabolical distortion of human character -- revenge. He embodies the 'A' for avenger. Torturing the man who has fathered a child with his wife becomes the sole purpose of Chillingworth's life. Then, through his determined searching, he discovers at last that Dimmesdale, too, has an 'A' on his heart corresponding to Hester's.
Chillingworth 's 'A' may also stand for alchemist and artist, for he is both.
[. . .]
From this allegiance of Chillingworth and the community come several other ironies. While the community thinks that the Black Man abides in the forest, he actually abides among them in the form of their honored guest and 'healer,' Chillingworth. And while the community believes that witchcraft is practiced somewhere in the depths of the forest, the most heinous black magic is practiced with their approval and cooperation right under their noses in Chillingworth's laboratory.
The conclusion that the reader is given to draw, then, is that Hester and Pearl are not respectively, lover and daughter of a Black Man or Satan who inhabits the forest. Rather -- it is the community itself which has a close relationship to the Black Man, in the person of Chillingworth, and encourages his dark arts.
Finally, in exploring the meaning of the "A," the reader arrives at Hawthorne's stated moral: 'Be true! Be true! Be true! Show freely to the world, if not your worst, yet some trait whereby the worst may be inferred!' (242). The true nature of every human is both sinful and angelic, somber and joyful, selfish and loving. To 'be true' means to recognize that we all wear a scarlet letter" (17-19).