Oscar de León
The novel centers on the "brief wondrous" life of Oscar, who is the opposite of the stereotypical Dominican men that the narrator knows. Oscar is smart, kind, loving, and obsessed with reading and writing science fiction and fantasy. He also struggles with depression and self-esteem issues because of his obesity and feelings of alienation. He struggles to fit in among his peers and has a difficult time with unrequited love. His romantic nature is obsessive and stubborn, a trait that eventually leads to his death.
Lola de León
Lola is Oscar's older sister and takes her own turn narrating at different points in the novel. Smart and kind, she constantly worries about Oscar and often comes to his rescue. Lola has a difficult relationship with her mother, Belicia, and begins to rebel against her in high school. After learning her mother's background from her grandmother, Lola begins to realize how similar they are in their rebellious and restless natures. Lola also has an off-and-on relationship with Yunior, and comes to rely on him to help her with Oscar.
Belicia de León
Belicia is Oscar and Lola's mother, who has a very stereotypically Dominican relationship with her children. While she worries over Oscar, she is harder on Lola, who is also rebellious in return. Belicia was born into a prestigious family but was passed around from relative to relative after her mother died. Her distant aunt, La Inca, rescues her from an abusive foster family, and Belicia finally attends a good school. She has bad luck in love, which causes her to fall for the Gangster. Her decisions lead her to being beaten by Trujillo's henchmen and forced to move to the United States for her own safety. She dies of breast cancer less than a year after Oscar's death.
Yunior is the main narrator of the novel. His investment in telling the story of Oscar and his family is the result of his off-and-on relationship with Lola, whom he loves deeply but can't seem to stay loyal to. Yunior sees himself as a typical masculine Dominican male, but secretly seems to have a lot in common with Oscar—a love for writing and an in-depth knowledge of science fiction and fantasy. Yunior believes in the family's curse and believes that by telling their story and filling in "the blank pages" he may be able to help the future generations of their family.
The de León family believes their curse can be traced back to Abelard, since he is the one who crossed Trujillo, which set many tragic events in motion. Abelard is a well-to-do, well-known scholar, and he tries not to draw the attention of the Trujillo regime to himself or his family. His decision to hide his beautiful daughter Jacqueline from Trujillo leads to his arrest, torture, and imprisonment. His wife is soon killed in a car accident, and his daughters are split up among their relatives. Abelard dies in jail alone many years later.
Although Lola and Oscar think of La Inca as their grandmother, she is in fact a relative of Abelard's who rescues Belicia from an abusive foster family when she is a young girl. La Inca runs a bakery in Baní, where she raises Belicia. La Inca is patient, kind, and loving, refusing to ever hurt Belicia physically because she knows there is abuse in her past. Her ability to pray holds an almost supernatural power after Belicia is kidnapped and assaulted, bringing her back from the brink of death. La Inca plays a similar maternal role to both Lola and Oscar, and her home serves as a familiar yet foreign escape for them when their own lives in New Jersey grow difficult. She allows them to be the persons they are without trying to change them, for which they both feel a secret relief.