Father Ambrosio, the most virtuous and learned monk in Madrid. He sentences Agnes de Medina to torture and death for adultery, and she calls upon him to remember her fate when he is tempted, as he is by Matilda, a sorceress. Following his seduction by Matilda, the monk ravishes Antonia, a virtuous girl. He is captured and condemned to die, but he sells his soul to Satan for release from prison. Satan releases him and then kills him after telling him that his victims, Antonia and Elvira, were his sister and his mother.
Matilda, a sorceress. She enters Ambrosio’s monastery disguised as a novice named Rosario. She seduces Ambrosio, leads him to ravish Antonia, and finally induces him to sell his soul. Matilda is condemned by the Inquisition but freed by Satan.
Antonia, a young girl ravished by Ambrosio and murdered by the monk to conceal his crime. Later, he learns that she was his sister.
Elvira, Antonia’s mother. She is killed by Ambrosio, who learns later that she was his mother.
Marquis Raymond de las Cisternas
Marquis Raymond de las Cisternas, a Spanish nobleman who is in love with Agnes de Medina and who is the father of her unborn child. After great difficulty, he rescues his beloved from the convent where she is imprisoned.
Agnes de Medina
Agnes de Medina, a young noblewoman who is condemned by Ambrosio for adultery. She is driven mad and almost starved to death in a convent.
Mother St. Clare
Mother St. Clare, a nun who mistreats Agnes de Medina.
Lorenzo de Medina
Lorenzo de Medina, Agnes’ brother, who aids in securing the release of his sister. He loves Antonia, but after her death he is comforted by Virginia de Villa Franca, whom he marries.
Virginia de Villa Franca
Virginia de Villa Franca, a wealthy heiress who helps restore Agnes de Medina to health and sanity. She falls in love with Agnes’ brother and marries him.
Mother St. Agatha
Mother St. Agatha, a nun who notifies Lorenzo de Medina falsely that his sister Agnes is dead.