The Narrator
We know little of his background, and we never even learn his name. He was childhood friends with Roderick Usher. He arrives on horseback at the house with the intention of helping Usher. Though he details precisely the nature of Usher's madness, it is suggested through the course of the narrative that he too may be losing his sanity. Indeed, given his terrified description of the ghastly house in the opening passages of the tale, the reader must wonder whether he was sane from the start.
Roderick Usher
The last living descendant, along with his ailing sister Madeline, of the Ushers, a time-worn family of wealth and prestige, known as patrons of the arts and givers of charity, but also stricken with a peculiar temperament that seems to run through their blood. Never having crossed lines with other families, the Usher name lies entirely "in the direct line of descent"--so that, after Madeline dies, Roderick is his family's sole living exponent. At the beginning of the story he already suffers from a severe mental illness, which steadily grows worse as the tale progresses. After his sister's death, he seems to retreat completely into madness. Before that precipitous fall, however, he dabbles in painting and shows himself to be an able guitar player. A man of culture and erudition, Roderick Usher spends his days inside his dark and cavernous mansion, avoiding sunlight or the smells of flowers, and obsessing over "the sentience of all vegetable things."
Madeline
Roderick Usher's sister. She suffers from a mysterious illness, cataleptic in nature, never otherwise explained. What is most important to the story, however, is the degree to which Roderick loves her. He seems unable to bear the thought of her death. The fact that the two of them live together without spouses in the great family mansion suggests, given the pecularity of the two and their unusual family history, the possibility of an incestuous relationship.