Lorenzo de Medina
A young man from the nobility of Madrid, Spain. He is the brother of Agnes and the friend of Christoval, and he is in love with Antonia. He is somewhat headstrong and very passionate, but quick to defend those he cares about. He struggles to discover what has become of his sister Agnes, and to prove himself worthy of Antonia.
Don Christoval
Best friend of Lorenzo, he is another young noble of Madrid. He is fond of the ladies, and has a very cheeky sense of humor.
Antonia
A beautiful young woman. Her mother, Elvira, was a commoner who eloped with a Marquis; in light of this, Antonia has lived much of her life in a castle. She is extremely innocent and naive, to the point that she is unaware of the anatomical difference between men and women. She attracts the interest of both Lorenzo and Ambrosio; the latter causes her ruin.
Leonella
Antonia's aunt and Elvira's sister, she is an old woman who is unafraid to speak her mind and has very strong opinions. An older woman who has never married, she often develops romantic interests in young men, including Christoval and an unnamed apothecary whom she marries.
Ambrosio
A monk of Madrid who is famous for his piety and elegant sermons. As a child, he was left at the doorstep of the monastery and brought up by the monastics. Eventually, he becomes consumed with pride at his accomplishments, and falls prey to temptation at the hands of Matilda. He commits greater and greater crimes, rationalizing them at each step of the way.
Rosario/Matilda
Originally known as Rosario, a promising novice monk, this character is revealed as Matilda - a woman who has posed as a monk in order to indulge her love for Ambrosio. Eventually, Matilda seduces Ambrosio and causes him to break his vows of chastity. Though he quickly loses interest in her, she uses her dark powers to assist him in his crimes.
Agnes
Lorenzo's sister, and the lover of Raymond. Her mother vowed to send her to a convent when she was born, though Agnes fiercely resists this fate. She falls in love with Raymond after he saves her aunt's life and moves into the castle where she is living. When their attempt to run away together fails, she assumes he has abandoned her and willingly becomes a nun. However, Raymond finds her, and the two resume their love affair, which leaves Agnes pregnant. When Agnes' pregnancy is discovered by the Prioress of the convent, she is subjected to horrible punishments.
Baptiste
Though he poses as an innocent woodsman, Baptiste is actually a robber who preys on the unwary. He tries to rob and kill Raymond, but Raymond overpowers him.
Marguerite
Wife of Baptiste. She was originally married to another robber who hid his profession from her, but when he died, Baptiste claimed her. She was raped and forcibly married to Baptiste, and endured this position in order to protect her two young sons from her first marriage.
Raymond
Friend of Lorenzo and lover of Agnes; he is a nobleman, the Marquis de las Cisternas. After graduating, he traveled Europe under the name “Alphonso d'Alvarada.” He is intelligent, brave, and handsome, and will stop at nothing to discover what happened to his beloved Agnes.
Rodolpha
The aunt of Agnes and Lorenzo. Raymond rescues her from the bandits, and she falls in love with him. She is filled with rage when she discovers that he is in love with her niece Agnes, and swears that she will take revenge on him. She separates the two lovers, but she dies from a brain aneurysm.
Theodore
Son of Marguerite, and Raymond's squire. He is a mischievous, intelligent boy who serves his master wholeheartedly, often finding ways to gain information about Agnes' situation. Theodore particularly enjoys writing.
The Prioress
Leader of the Convent of St. Clare. She is known for her strict, rather cruel nature; she is determined that her convent become the most fashionable in all Madrid. When she discovers that Agnes has broken her vows of chastity, she vows to punish her in the harshest ways. Eventually, the Prioress falls victim to a mob that stones her to death.
Cunegonda
Agnes' governess. She overhears Raymond's plan to elope with Agnes, so Raymond and Theodore keep her prisoner.
Elvira
Mother of Antonia. She is a beautiful but weary woman; she incurred a great deal of trouble by eloping with the son of a Marquis and moving to the West Indies with him. She is worldly and intelligent. She loves her daughter Antonia deeply, and dies when she attempts to protect her daughter from Ambrosio. At the end of the novel it is revealed that she is the mother of Ambrosio.
Mother St. Ursula
A nun at the convent of St. Clare. She is the one who reveals Agnes' true fate to Raymond, Lorenzo, and the rest of Madrid.
Virginia de Villa Franca
A beautiful young woman who leaves the convent of St. Clare after it is burned and looted. She eventually marries Lorenzo.
Don Ramirez
A friend of Lorenzo's, he commands a number of archers who help to confront to Prioress at the procession of St. Clare.
