Aylmer
An accomplished yet misguided scientist, Aylmer has made revolutionary discoveries about the physical world, from volcanoes to clouds to mines. His risky investigations into the spiritual world, meanwhile, are evidence of his aspiration to be God-like—his desire to change Nature's creations. For example, Aylmer believes he can concoct an elixir vitae—a potion that will render the drinker immortal—and becomes obsessed with his outlandishly ambitious experiments and pursuit for human perfection. Early in the story, the narrator comments that “he has devoted himself … too unreservedly to scientific studies ever to be weaned from them by any second passion" (152). Though Aylmer tries to devote himself to a “second passion,” i.e. his wife, Georgiana, but she soon becomes the subject of one of his experiments (152).
Aylmer views the red hand-shaped birthmark on Georgiana’s cheek as a grotesque imperfection belonging to an otherwise perfect human. Rather than accept the physical flaw and protect her safety, Aylmer performs a risky procedure to rid her skin of the mark, which results in her death. In other words, Aylmer triumphs the sheer drive for control and scientific success over his relationship with his own wife. Because of his overly pragmatic mind that operates outside of decency and morality, Aylmer's character shows us the dangers of unchecked ambition and intellect, as well as the limitations of scientific pursuits.
Georgiana
As Aylmer’s beautiful and caring wife, Georgiana is a physically ideal woman, with the exception of the small, hand-shaped birthmark on her cheek. While most men are charmed by her birthmark, Aylmer is horrified by it. Because she expresses an utmost allegiance to her husband, Georgiana begins to resent her appearance and birthmark just as Aylmer does. Georgiana submits to Aylmer and only cares about what he thinks of her, and she becomes the subject of one of his dangerous, life-threatening experiments as a result. By trusting her husband at all costs and surrendering to his outrageous demands, she adheres to normative gender roles that demand a woman’s obedience and subordination to a man.
However, in spite of her powerless position in the story, Georgiana is highly intelligent and reads works of philosophy and accounts of her husband’s experiments. She also proves to be more morally upright than her husband, as she willingly puts herself in danger for the happiness of another person. Georgiana even regains her self-confidence moments before her death; she tells Aylmer, “you have rejected the best the earth could offer” (165). As a foil to Aylmer's moral ambiguity, Georgiana emerges as the story's true hero—she's infinitely more sympathetic and selfless than her husband.
Aminadab
Aminadab is Aylmer’s grotesque, physically-strong lab assistant and servant. Describing Aminadab's short and bulky stature, shaggy hair, and “uncouth, misshapen tones,” Hawthorne uses dehumanizing language to characterize him as more beast than man (159). Aminadab is an able assistant, but he expresses a dislike for Aylmer’s chase for perfection. He even announces that if he was Georgiana’s husband, he would not have her birthmark erased. Thus, while described in abject terms by Hawthorne, Aminadab is arguably a more humane and compassionate character than Aylmer.