Borachio is one of the comic characters, the servant of Lothario. He speaks almost entirely in proverbs and clichés, a fact which several characters note. Unlike Lothario, Borachio is not impressed with court life and several times mentions plans to return home to his wife. Nevertheless, he believes the lies of Castruchio, Dorido and Cosimo, who pretend that Lothario is a favorite of the Duke. When Lothario is talked into challenging Foreste's heritage and is taken by Foreste's servants, Borachio runs away. He complains to Castruchio about the conditions of Lothario's imprisonment, asking how the Duke could imprison his favorite, and is overjoyed when told Lothario is freed. When Castruchio incites Lothario against Foreste, Borachio attempts to stop him, but is not listened to by either. He promises to follow Lothario, but then disappears from the play and is not part of the final tragedy.
BORACHIO'S WIFE
A "ghost character." Borachio mentions his wife several times, always in the context of leaving the court to return to her, and how happy this will make her.
BOY
The boy is a singer who accompanies Corsa to Foreste's house after her rape. He sings a song about the need to accept what Providence brings. Corsa dismisses him on Foreste's command.
CARDINAL
A "ghost character." The Cardinal is the Duke's brother and sends him a letter confirming a truce with Genoa, a fact which upsets the Duke.
CASTRUCHIO
Castruchio is a satirical courtier, related to the melancholic. He employs a Singer to sing his satirical verses about courtiers, and complains constantly to his cousin Cosimo about the corrupt and unfair state of the world. He is especially appalled by the Duke's favors towards both Lucio and Foreste, the first because he is so young and the second because he is not noble. However, he attempts to win Foreste's favor as a means to approach the Duke about a monopoly. When Foreste rejects the notion of monopolies violently, they begin a duel during which Foreste disarms Castruchio, but they are discovered before any blood can be shed. Castruchio plays with Lothario, making him believe first that he is the Duke's favorite and then that Foreste has ruined that favor, urging him to confront Foreste, an action that ends with Lothario in jail. Castruchio is then approached by the Duke for aid in gaining Corsa. Castruchio, through his relationship with Duarte, brings the Duke to Corsa's bedroom and calms Duarte's fears that it is rape, not seduction, that is taking place. Castruchio then has Lothario freed from prison and encourages him to take revenge on Foreste. When the Duke becomes fearful that Corsa will reveal his rape, Castruchio suggests that he lie in wait for Lucio and Foreste and kill them. The Duke at first agrees, but then makes Castruchio promise not to kill Lucio. In the fight in the dark that follows, Castruchio is wounded by Foreste and tries to flee with Cosimo, but both are taken and returned to the scene, where all is revealed. Dorido promises that Castruchio and Cosimo will be tortured before their execution.
CASTRUCHIO'S SINGER
A "ghost character." Castruchio's singer is mentioned by Dorido and Cosimo, who comment that he sings Castruchio's libelous songs and is a big man.
CORSA
Corsa is the sister of Foreste and becomes the wife of Lucio. Having already declared to Foreste his desire to marry her, Lucio arrives at their house and asks for her hand. Foreste is unsure because she has no dowry but chastity, and he does not want to be a charity case, but he eventually agrees. Corsa is not consulted, but she seems as happy as Lucio about the marriage. In an odd moment, after declaring he will only look on her, Lucio covers her face with her veil because otherwise he will be overwhelmed, perhaps foreshadowing both the damage her beauty will cause and her early death. After the Duke forgives Lucio and Foreste for the marriage, Corsa enters and is teased by the Duke, but she either does not or pretends not to understand the sexual connotations of his jokes. When the Duke sends her a brooch by Luinna she is at first uneasy about the gift, but Luinna convinces her that it is innocent. She is then approached by the Duke offstage, and when she resists him, is raped–these events are narrated by Castruchio and Duarte. She dismisses Duarte, but not before giving her money for a pilgrimage and asking her to speak well of her mistress. She travels to her brother's house, where Foreste tells her that she must die, even though she was forced. She agrees, and allows him to slit her wrist. She dies concerned about her reputation, and on her death mystical music plays.
COSIMO
Cosimo is a courtier and cousin to Castruchio. He lives mainly in Castruchio's shadow and then usually to support what Castruchio has said, although he does tease his cousin about his supposed love, the otherwise unnamed Great Lady. He agrees to help Castruchio kill Foreste and Lucio. After Lothario kills the Duke, thinking it is Foreste, Cosimo kills Lothario on Castruchio's command and then fights with Lucio and is wounded while wounding Lucio in turn. Cosimo and Castruchio attempt to escape, but they are captured by Dorido and promised torture and death.
DEAD MONK
A "ghost character." The Monk asks Foreste's help in gaining the Duke's preferment and the place of the dead monk. Foreste promises to help him, but his cause is never mentioned.
DORIDO
Dorido is a courtier and at first a friend of Cosimo, but it is clear from the first scene, when he will not speak ill of Lucio or Foreste, that he is not a villain. With Cosimo and Castruchio, he makes fun of Lothario and Borachio, but is not present when Castruchio convinces Lothario to attack Foreste. Dorido becomes suspicious of the Duke and Castruchio, and follows them to Lucio's house the night the Duke rapes Corsa. He overhears Castruchio and Duarte and learns everything, and swears to bring the crime to light. With an unnamed and silent friend, he helps Foreste prove that Luinna is chaste, entering in masks while Foreste promises to hand over Luinna to them. After the threat and Luinna's response, Dorido states that he believes, and always has, that Luinna is faithful. Dorido apprehends Castruchio and Cosimo after they have fought with Lucio and Foreste and, since the Duke is dead, takes command of the situation (and apparently the state).
DORIDO'S SISTER
A "ghost character" and possibly fictional. Dorido tells Cosimo that he has been challenged to a duel because his sister drank the Duke's health with her hat on. However, since the point of the entire speech is to satirize how quickly men are willing to fight, and over what trifles, it is possible that Dorido has no actual sister.
DUARTE
Duarte is the handmaid to Corsa. She is romantically involved with Castruchio, who uses that relationship to gain the Duke access to Corsa's bedroom. Duarte is troubled by what takes place, citing Corsa's shrieks as evidence that she was not willing, and regrets allowing the Duke access. But she is persuaded by Castruchio that women are like wax, willing to accept any impression. When Corsa confronts her maid, Duarte attempts to excuse both of them by pointing out that other women have done worse, but she is dismissed by Corsa, who gives her money to go on pilgrimage and pray for Corsa's "fault."
DUKE
The Duke at first appears to be a perfectly moral man. He is appalled by the press of suitors begging for unearned favors and promotes Foreste to the position of secretary based on his worth rather than birth. When Foreste and Lucio beg pardon for Lucio's marriage to Corsa, the Duke forgives them before he even knows the fault. The first sign of a malevolent character comes when he teases Corsa about how her "use" of Lucio has weakened him and drained him of his beauties. The Duke then immediately sets about trying to seduce Corsa, first stating that she will be high in his favor if she will recant her out-of-fashion modesty, then sending her jewelry through Luinna, and finally gaining direct access to her through Duarte's treachery, after sending Lucio away for a day. Before the rape, he worries about betraying Lucio's love, and afterwards, he first asks Castruchio to make him safe from discovery, but then insists that Lucio not be hurt. When Foreste and Lucio confront the Duke in his chamber, Lucio insists that they cannot kill their Prince. In all, the homosexual subtext barely remains under the surface. After they leave, the Duke follows them to warn them of Castruchio, Cosimo and Lothario, who are waiting to kill Foreste, and is himself killed by Lothario who mistakes him for Foreste.
ENGLISH–LEIGER
A "ghost character." Foreste describes how the French Ambassador complained about the English Leiger and his opposition to a proposed treaty.
FARELO DE SFORZA
A "ghost character." Farelo de Sforza was the Duke's secretary and, on his death, the Duke appoints Foreste to his position.
FLORENTINE MUSIC TEACHER
A "ghost character." When Lucio comes to visit Foreste and Corsa, he hears music and is informed by Foreste that it is the Florentine, who instructs Corsa in music.
FORESTE
Foreste is the title character and of common birth. He is a friend of Lucio's, despite his lower rank. He is exceptionally moralistic and in fact objects to Lucio's desire to marry Corsa, Foreste's sister, because she is not worthy of a Count. When Castruchio asks Foreste to help him win a monopoly, Foreste is so insulted that they begin a duel, during which Foreste disarms Castruchio. The entrance of the Monk stops the duel before blood can be shed. The Duke appoints Foreste his secretary because of his worth and, although it is never stated, it seems this overcomes Foreste's objections and allows Lucio and Corsa to marry. Despite his new position, Foreste still refuses to help a Gentleman gain an unwarranted captaincy. Foreste is next insulted by Lothario, who is set on by Castruchio, but once again Foreste is victorious and Lothario is put in jail. He is freed by Castruchio, and swears vengeance on Foreste. When Foreste finds the brooch that the Duke gave to Foreste's wife, Luinna, Foreste accuses her of infidelity and cruelly tests her by pretending to hand her over to a pair of rapists. He is satisfied by her protestations of innocence, but barely, and later drags her along to the Duke's bedroom to confront the Duke. When Foreste finds out about Corsa's rape, he decides that she must die immediately because, even if she were forced, she will lose her reputation. She agrees, and Foreste slits her wrist and declaims upon reputation and impure blood while she bleeds to death on stage. When Lucio returns and finds her dead, Foreste is surprised to find Lucio is not grateful for his service, and even suggests killing himself for having upset his friend. Instead, he suggests that they take revenge on the Duke. When they confront the Duke in his bedroom, Foreste presents Luinna and demands to know if the Duke has slept with her. The Duke's declaration that she was only a way to get to Corsa finally satisfies Foreste. He is disgusted that Lucio forgives the Duke, out of his duty to the sovereign, but accepts Lucio's decision. In the final fight scene, Foreste fights with Castruchio and wounds him, but is killed himself.
FRENCH AMBASSADOR
A "ghost character." The Duke asks if the French Ambassador demonstrated discontent after meeting with the Duke. Foreste confirms that he was angry at the English-Leiger for opposing a proposed treaty.
FRIEND, DORIDO'S
An unnamed and silent friend. He accompanies Dorido as he helps Foreste prove that Luinna is chaste. He and Dorido appear as rapists in masks while Foreste promises to hand over Luinna to them.
GENTLEMAN
The Gentleman seeks preferment with the Duke and seeks out Lucio and Foreste for help. But when they find out that the Gentleman wants a captaincy, they are appalled at the idea of a young, untested man being given command rather than a seasoned solider and reject him scornfully.
GREAT LADY
A "ghost character" and possibly fictional. Cosimo and Dorido tease Castruchio about a Great Lady who hires Castruchio to write verses against the lechery of women in order to cover her own affair with Castruchio. Castruchio neither confirms nor denies the existence of such a patron.
HIS HOLINESS
A "ghost character." The Duke asks Foreste if letters have been sent to His Holiness (probably the Pope).
LADY BENVOLIA
A "ghost character." This is one of the two ladies that Corsa guesses was Luinna's nighttime visitor (who was actually the Duke).
LADY UTRUVIA
A "ghost character." This is one of the two ladies that Corsa guesses was Luinna's nighttime visitor (who was actually the Duke).
LOTHARIO
Lothario is a self-important courtier and comic figure who believes he is much more important than he really is. He dresses ridiculously, believing it is the height of fashion. He is easily convinced by Castruchio and Cosimo first that he is actually one of the Duke's favorites (despite never having spoken to the Duke) and then that Foreste has destroyed that favor. He threatens Foreste with a false pedigree, showing Foreste to be the son of hangmen and whores, but Foreste quickly has him thrown in jail. He is released by Castruchio and, despite the pleas of his servant Borachio, agrees to seek revenge on Foreste. With Castruchio and Cosimo, he waits in the palace for Foreste and Lucio, who are coming to confront the Duke, but in the dark Castruchio mistakes the Duke for Foreste. Lothario attacks and kills the Duke, and is then killed by Cosimo on Castruchio's orders.
LUCIO
Lucio is a young courtier, much beloved of the Duke, and friend to Foreste. Lucio is in love with Corsa, Foreste's sister, and wins her hand despite Foreste's fears that she is not worthy of him. Lucio and Foreste appear before the Duke to ask pardon for Lucio's marriage, and the Duke grants it, while teasing Corsa about using up Lucio's health and beauty. The Duke then sends Lucio to Lucca, ostensibly to greet the Papal Legate, but really to allow the Duke a chance to seduce Corsa. After the rape, Corsa sends for Lucio, asking him to return immediately, which he does, but he finds her dead. Foreste explains that he himself killed her because she had been stained. Lucio is not at all impressed with his argument, and states instead that since she was forced, her thoughts are pure. He attacks Foreste, who refuses to fight back and instead says that he killed a sister to keep a friend, but since he has done wrong he deserves to die. Lucio refuses to kill him, and Foreste then suggests that they take revenge on the Duke. After Foreste has confronted the Duke about Luinna and been satisfied, Lucio prepares to kill him, a death which the Duke seeks. Lucio, however, cannot bring himself to kill his prince. When Foreste points out that the Duke will surely have them killed to secure himself, Lucio responds that he welcomes death. After leaving the bedroom, they find the Duke killed by mistake, and Lucio attacks the men who killed his prince. In the final fight, Lucio fights with Cosimo and wounds him, but is killed himself.
LUINNA
Luinna is the wife of Foreste. We first see her as Foreste lectures her not to take too much pride in his elevation to Duke's secretary. Apparently Luinna is also responsible for keeping Corsa humble despite Lucio's marriage proposal. Both these things Luinna promises to do. After Corsa's marriage, the Duke gives Luinna a brooch and asks her to deliver another to Corsa. Corsa is concerned that the Duke may have dishonorable motives for the gift, but Luinna has been convinced otherwise. Nevertheless, she decides to hide the brooch from Foreste. Incredibly, after Corsa is raped, Luinna's response is that Foreste has found the jewelry and thinks that she has been unfaithful. Corsa actually has to calm her sister-in-law and give her advice, which is to trust Foreste's love. This turns out to be good advice, but barely. Foreste believes that she is unfaithful and pretends to offer her to Dorido and another man, who are masked, in order to scare her into confessing. Luinna does confess, but to Corsa's rape by the Duke. Foreste seems convinced, although he insists that Luinna stay locked up. When Lucio and Foreste go to confront the Duke in his bedroom, Luinna goes as well, and Foreste asks the Duke what has happened. When the Duke admits that he only gave Luinna a brooch to disguise his interest in Corsa, Foreste seems finally satisfied. During the climactic fight scene, Luinna runs for help and then mourns for her dead husband.
MARQUISS DE LORETTA
A "ghost character." The Gentleman brings a letter from the Marquiss de Loretta asking that Lucio and Foreste help the Gentleman gain a captaincy. The suit is denied.
MONK
The Monk comes upon Foreste and Castruchio dueling in time to stop bloodshed. He asks Foreste's help in gaining the Duke's preferment and the place of the dead monk. Foreste promises to help him, but his cause is never mentioned.
PETRUCHIO
A "ghost character." Petruchio, described as "the great" by Dorido, was Foreste's commander. Dorido tries to use his name to make Foreste believe his honesty.
POPE'S LEGATE
A "ghost character." Lucio is sent to Lucca, ostensibly to greet the Pope's Legate, but really so that the Duke can attempt to seduce Corsa.
SERVANT
The Servant, along with an unspecified number of other, mute Servants, helps subdue Lothario and tells him to be quiet.
SUITORS
Three suitors who seek the Duke's preferment figure in the play.
The First Suitor seems the most unaware of the Duke's movements, and follows the Second Suitor in search of the Duke and Lucio.
The Second Suitor seems to know where they are and promises to show the others the way.
The Third Suitor specifically seeks Lucio, presumably as a way to the Duke.