Estha, which is short for Esthappen Yako, is Rahel's twin brother. He is a serious, intelligent, and somewhat nervous child who wears "beige and pointy shoes" and has an "Elvis puff." His experience of the circumstances surrounding Sophie's visit is somewhat more traumatic than Rahel's, beginning when he is sexually abused by a man at a theater. The narrator emphasizes that Estha's "Two Thoughts" in the pickle factory, stemming from this experience—that "Anything can happen to Anyone" and that "It's best to be prepared"—are critical in leading to his cousin's death.
Estha is the twin chosen by Baby Kochamma, because he is more "practical" and "responsible," to go into Velutha's cell at the end of the book and condemn him as his and Rahel's abductor. This trauma, in addition to the trauma of being shipped (or "Returned") to Calcutta to live with his father, contributes to Estha's becoming mute at some point in his childhood. He never goes to college and acquires a number of habits, such as wandering on very long walks and obsessively cleaning his clothes. He is so close to his sister that the narrator describes them as one person, despite having been separated for most of their lives. He is repeatedly referred to as "Silent."
Rahel is the partial narrator of the story, and is Estha's younger sister by 18 minutes. As a girl of seven, her hair sits "on top of her head like a fountain" in a "Love-in-Tokyo" band, and she often wears red-tinted plastic sunglasses with yellow rims. An intelligent and straightforward person who has never felt socially comfortable, she is impulsive and wild, and it is implied that everyone but Velutha treats her as somehow lesser than her brother. In later life, she becomes something of a drifter; several times, the narrator refers to her "Emptiness." After the tragedy that forms the core of the story, she remains with her mother, later training as an architectural draftsman and engaging in a failed relationship with a European, elements of which parallel the author's own life story.
Ammu is Rahel's and Estha's mother. She married their father (referred to as Baba) only to get away from her family. He was an alcoholic, and she divorced him when he started to be violent toward her and her children. She went back to Ayemenem, where people avoided her on the days when the radio played "her music" and she got a wild look in her eyes. When the twins are seven, she has an affair with Velutha. This relationship is one of the cataclysmic events in the novel. She is a strict mother, and her children worry about losing her love.
Velutha is a Paravan, an Untouchable, who is exceptionally smart and works as a carpenter at the Ipe family's pickle factory. His name means white in Malayalam, because he is so dark. He returns to Ayemenem to help his father, Vellya Paapen, take care of his brother, who was paralyzed in an accident. He is an active member of the Marxist movement. Velutha is extremely kind to the twins, and has an affair with Ammu for which he is brutally punished.
Chacko is Estha's and Rahel's maternal uncle. He is four years elder to Ammu. He meets Margaret in his final year at Oxford and marries her afterward. They have a daughter, Sophie, whose death in Ayemenem is central to the story.
Baby Kochamma is the twins' maternal great aunt. She is of petite build as a young woman but becomes enormously overweight, with "a mole on her neck," by the time of Sophie's death. She maintains an attitude of superiority because of her education as a garden designer in the United States and her burning, unrequited love for an Irish Catholic priest, her relationship with whom is the only meaningful event in her life. Her own emptiness and failure spark bitter spite for her sister's children, further driven by her prudish code of conventional values. Her spite ultimately condemns the twins, the lovers, and herself to a lifetime of misery.