If Judge Jaffrey Pyncheon is a jerk who looks like a nice guy, his cousin Hepzibah is the opposite: she looks mean but she has a heart of gold. Where Judge Pyncheon's most recognizable characteristic is his kindly smile, Hepzibah's is her dark scowl. She doesn't mean to scowl; it's just that she's near-sighted and has heavy eyebrows. She has to squint all the time, which makes her look angry. She is actually tender-hearted, as her devoted care for her brother Clifford shows.
Hepzibah is a woman of about 60. She has been living by herself in the House of the Seven Gables for the last 30 years, ever since her brother Clifford was unjustly sent to jail. All of this time, she has been refusing offers of financial help from her jolly cousin Judge Pyncheon. She knows what he is, even if the rest of society falls for his mask of pleasant kindness.
By living isolated from society for so long, Hepzibah has become very strange and sad. She has filled herself with notions of being a "lady," so she thinks she's too good to earn her own living. She's grown thin, pale, and washed out: she is both physically and spiritually ghostly. The narrator sums up Hepzibah's character in a nutshell here:
Hepzibah, though she had her valuable and redeeming traits, had grown to be a kind of lunatic by imprisoning herself so long in one place, with no other company than a single series of ideas, and but one affection, and one bitter sense of wrong. (12.3)
That one affection is, of course, for her brother Clifford. The bitter sense of wrong is his false imprisonment by Judge Pyncheon. The narrator thinks, as we do, that Hepzibah really needs to get out more. Luckily, several changes – her shop, her brother, and the death of Judge Pyncheon – ensure that she does.
At the start of the novel, we meet Hepzibah at her lowest moment, as she is trying to open a small shop at the side of the House of the Seven Gables. The thing is, Hepzibah is on the edge of starvation, so she has no choice but to try her hand at trade. Yet there is no one on earth less suited for this work: she has too much wounded pride and is too uncomfortable with people to manage a store properly. Luckily for Hepzibah, Phoebe arrives out of the blue and saves her. Still, this moment when Hepzibah decides to open the store shows a loosening in her iron-clad notions of family honor and being a gentlewoman. She begins to join the modern world once she opens her shop, which is hugely good for her.
The other thing that's good for Hepzibah is to get her brother Clifford back from jail. She's been grieving for him for 30 years, and once he's back, she dedicates herself unselfishly to his happiness. She arranges for Phoebe to take care of him (since he loves beauty too much to enjoy poor Hepzibah's company), and she does her best to provide him a loving home.
Hepzibah's love of Clifford drives her to stand up to Judge Pyncheon at last. During her first direct confrontation with him, Hepzibah says feebly: "O Phoebe! [...] that man has been the horror of my life! Shall I never, never have the courage […to tell] him what he is?" (8.52). Hepzibah does indeed work up the courage to tell Judge Pyncheon outright: "You hate [Clifford]! Say so, like a man!" (15.14). Hepzibah's strength at this moment provokes Judge Pyncheon to tell the truth of his plans, which leads indirectly to his sudden death by stroke in the parlor. Without Hepzibah's hidden courage, she and Clifford would never have been free of Judge Pyncheon's self-righteous bullying.