He dies the night of the fire after being locked by Jorge in the secret stairwell that leads to the hidden room in the library the monks call the finis Africae.

Adelmo of Otranto

The first of the monks to be found dead, Adelmo was a talented and handsome young illuminator. His body was discovered on the mountainside below the abbey just prior to Adso and William’s arrival, and his death prompts their investigation. It is later revealed that Adelmo had a sexual relationship with Berengar of Arundel. It was the guilt and torment he felt over this relationship after receiving confession from Jorge that led Adelmo to leap to his death.

Remigio of Varagine

The abbey’s cellarer, Remigio is described as jolly but vulgar, with white hair and a small but strong build. He and his assistant, Salvatore, originally came to the abbey fleeing persecution as former Fraticelli, followers of the now-condemned heretic Fra Dolcino. Remigio has Salvatore bring him young women from the nearby village by night so that he can trade them scraps of food for sexual favors. He is later betrayed by Salvatore and tried by the inquisitor Bernard Gui. During his trial, he confesses to all manner of crimes and heresies, declaring his unwavering faith in the ideals of the Fraticelli. He is then taken to Avignon to be burned at the stake.

Salvatore

Salvatore stands out among the monks for his strange way of speaking, which consists of a hodgepodge of words from different European languages and regions. Described as an incredibly ugly old man, Salvatore acts as assistant to Remigio, the cellarer, with whom he came to the abbey. Salvatore was born into the peasantry and spent most of his life wandering the countryside before joining up with Fra Dolcino’s band. He eventually betrays Remigio, and together the two are arrested and taken to Avignon.

Ubertino of Casale

A Franciscan monk, mystic author, and old friend and mentor of William, Ubertino has come to the abbey fleeing persecution as a leader of the Spirituals, monks who advocate a life of poverty. He is a sixty-eight-year-old man with large blue eyes, and Adso describes him as resembling a withered maiden. Ubertino is passionate about his mystical beliefs; he urges William to abandon his scholarly ways and Adso to devote himself to holy love, or mystical communion with God. He flees the abbey after talks between the delegations from Emperor Louis and Pope John fall apart, and his death two years later is shrouded in mystery.

Severinus of Sankt Wendel

A learned herbalist about the same age as William, Severinus is in charge of the infirmary, balneary, and gardens and understands both the medicinal and harmful properties of countless plants. He also supplies Malachi with the herbs used to disorient intruders in the library. Severinus is murdered by Malachi when the jealous librarian hits him over the head with an armillary sphere, making him the fourth monk to die.

Malachi of Hildesheim

As librarian, Malachi is the only person at the abbey other than his assistant, Berengar, who may enter the library. He understands its labyrinthine construction and complicated system of organization. Adso describes him as tall, thin, middle-aged, melancholy, and resembling an old woman. Malachi has, or once had, a sexual relationship with his assistant, Berengar. He murders the herbalist Severinus in a fit of jealousy, convinced by Jorge that Berengar slept with Severinus in exchange for a forbidden book. Malachi then succumbs to the poison on the lost book of Aristotle and collapses during Matins, making him the fifth monk to die.

Jorge of Burgos

At over eighty years old, Jorge is the second-oldest monk at the abbey and has been blind for at least forty years. He has the unsettling ability to sneak up on people in complete silence. He is also an incredibly grim figure who acts as confessor for the other monks, preaching against laughter, pagan learning, and immorality, and often warning of the coming of the Antichrist. Jorge holds particular influence over Malachi and seems to know more about the books in the library than the librarian himself. In his climactic confrontation with William and Adso, it is revealed that Jorge, believing that God had charged him with the task of preventing the spread of dangerous ideas, placed poison on the pages of Aristotle’s lost book on laughter, which he had had Malachi hide in the finis Africae decades ago. He is also responsible for the death of Abo, whom he locks in the secret passage from the refectory to the finis Africae, and can be seen as partially responsible for the deaths of Adelmo and Severinus. Jorge dies in the library after eating the poisoned pages of the book and throwing the rest into the fire he has accidentally started. He is then knocked into a bookcase by William and left to his fate in the conflagration.

Venantius of Salvemec

Venantius is a translator of Greek and Arabic and a devotee of Aristotle. He was close to Adelmo and learned of the existence of Aristotle’s lost book on comedy from Berengar. He is the second monk to die, and William discovers how to penetrate the finis Africae by translating the explanation Venantius wrote in code and left in the scriptorium. Though Venantius died in the kitchen after being poisoned, his body is found upside down in a jar of pig’s blood after having been placed there by Berengar.

Berengar of Arundel

Assistant librarian to Malachi, Berengar is a young monk described as pale, with the same eyes “of a lascivious woman” as his closest friend, Adelmo. Berengar is aware of the secret of the finis Africae and shared what he knew with Adelmo and Venantius prior to William and Adso’s arrival. He is the third monk to be found dead, drowned in the balneary after being poisoned. Berengar shared a sexual relationship with Malachi and later with Adelmo, for whom he had a great passion. Adelmo felt so much guilt over this relationship after confessing it to Jorge that he committed suicide. Berengar was the last person to see Adelmo alive, although he believed he was seeing a ghost.

Nicholas of Morimondo

The abbey’s master glazier. Nicholas is impressed by William’s spectacles and makes new ones for him after the originals are stolen by Berengar. He also tells William and Adso of rumors in the abbey that the library is protected by magic and that monks who venture into it at night are driven mad by visions. After the arrest of Remigio, Nicholas becomes the new cellarer.

Alinardo of Grottaferrata

The oldest monk at the abbey, Alinardo is frail and absentminded. He is at the center of a group Adso refers to as “the Italians”; they sympathize with Alinardo’s long-held grudge against Jorge and agree that as a foreigner, Jorge should not have been  appointed librarian—and therefore future abbot, had Abo not been given the position—instead of Alinardo. Alinardo dies after being knocked down by the horse Brunellus during the fire.

Benno of Uppsala

A young Scandinavian student of rhetoric with an appreciation for the pagan writers. Chosen by Malachi as the new assistant librarian after the death of Berengar, Benno is driven by a lust for knowledge and a passion for books. Benno later reveals that he stole the lost book of Aristotle from the infirmary after Severinus was found murdered and returned it to Malachi, thus securing his appointment to the recently vacated post of assistant librarian. During the fire at the novel’s end, Benno dies after rushing into the burning library.

The peasant girl

Adso has the first and only sexual or romantic experience of his life with a beautiful girl from the nearby village whom he encounters in the kitchen after making a nighttime trip to the library. She had been brought there by Salvatore for Remigio, who would have traded her scraps of food for sexual favors. Salvatore, however, flees the scene, and Adso and the girl, who remains unnamed, sleep together. It is a transcendent experience for Adso, who sees her as pure and holy. Tragically, the girl is accused of witchcraft by Bernard Gui and taken to be burned at the stake in Avignon along with Salvatore and Remigio, causing Adso to reflect that the “simple folk” will always be made to unjustly suffer when the powerful quarrel.

Bernard Gui

A seventy-year-old Dominican monk and inquisitor who arrives with a delegation from the Pope in Avignon. Adso is struck by Bernard’s gray eyes, which Bernard can make seem expressionless or use to express certain emotions at will. As he reveals during his trial of Remigio, Bernard is a skilled inquisitor, manipulating the cellarer into confessing all manner of sins. He has a particularly antagonistic relationship with William and does not hesitate to convict Remigio, Salvatore, and the village girl of murder, heresy, and witchcraft.

The narrator of The Name of The Rose is Adso of Melk. As a young novice during the events he recounts, he becomes an old man by the time he documents them. Adso the novice has a naive and ingenuous nature. His mind is open, his heart is vulnerable, and his soul remains pure. Like William, he possesses a genuine, unbiased curiosity. Without allegiance to any faction, Adso is free from the prejudices that many older characters exhibit. However, he also lacks the patience seen in many of the other characters. Unlike William, who frequently emphasizes his own limitations and credits God for all knowledge and wisdom, Adso often finds himself either pleased or frustrated by their discoveries. Adso serves as a Watson to William's Sherlock Holmes.

William of Baskerville, a Franciscan monk, is the central figure — the detective — in The Name of The Rose. A friend of Roger Bacon and William of Occam, William comes to the monastery as a representative of the Franciscan order and Emperor Louis IV to arrange a meeting with a papal legation. Soon, the Abbot enlists William to investigate the mysterious death of a monk.

As more deaths occur, William becomes increasingly determined to solve the mystery, suspecting a single murderer might be behind the killings, which seem to follow the events described in the Book of Revelations. William quickly deduces that each monk's death is linked to a manuscript within the monastery library. The library itself, much like Eco's novel, is a labyrinth, with its truths safeguarded by a complex puzzle. Some critics suggest that William is clearly Eco's hero and possibly his spokesperson. Indeed, William is a medieval semiotician who explains his investigative method to Adso: "The idea is sign of things, and the image is sign of the idea, sign of a sign." More importantly, both William and Eco compellingly argue for the significance and power of laughter.

Abo

Abo serves as the abbot of the Benedictine abbey and requests William to investigate the murders of several monks. Abo prioritizes the abbey's reputation over uncovering the truth. By the novel's conclusion, Abo himself becomes a murder victim.

Adelmo of Otranto

Adelmo is a young manuscript illustrator. Before the story begins, he engages in a homosexual relationship with Berengar, potentially to access a significant, restricted book. He commits suicide shortly before William and Adso arrive at the abbey.

Adso of Melk

Adso of Melk is an elderly Benedictine monk recounting his experiences as a young novice who accompanied William of Baskervilles to a northern Italian abbey in 1327, where they encountered multiple murders. Adso plays dual roles in the narrative: as an older, reflective voice and as a young, innocent novice, the younger son of a wealthy nobleman dedicated to the church. The Name of the Rose is essentially Adso’s coming-of-age story; he loses his virginity to a peasant girl and evolves from ignorance to knowledge. He faces the era's critical theological debates at the abbey and witnesses a thirst for knowledge leading several young monks to their deaths. Adso also functions as “Watson” to William’s “Sherlock” in solving the murders. Eco intended for readers to associate Adso with Watson, as “Adso” is pronounced similarly to Watson in Italian and French. Adso's simple questions enable William to elaborate on his theories and methods, echoing the dynamic between Dr. Watson and Sherlock Holmes in Sir Arthur Conan Doyle's stories. Ironically, Adso's casual remarks often provide crucial clues for William.

Benno of Uppsala

Benno is a rhetorician who studies language figures. He perishes while attempting to save books from the library, succumbing to the flames.

Berengar of Arundel

Berengar, the assistant librarian at the abbey, is privy to many of its secrets. He is also a homosexual who has had affairs with both Malachi, the chief librarian, and Adelmo. Berengar is murdered by being poisoned with a toxic book.

Bernard of Gui

Bernard is a genuine historical figure who played a significant role as a judge in the Inquisition, condemning numerous heretics to death by fire. In this novel, Eco depicts Bernard as an inquisitor who, in his relentless quest for the Truth, subjects suspects to torture and the threat of a gruesome death. His methods of inquisition lead to confessions; however, it becomes evident that, despite obtaining confessions, he fails to uncover the truth behind the murders. His primary function in the novel is to serve as a foil for William, whose views on truth, orthodoxy, and heresy starkly contrast with Bernard’s.

Jorge of Burgos

Jorge is a blind, elderly monk with extensive knowledge about books and the library. (Later in the story, William deduces that Jorge was once the head librarian.) In one of the novel's crucial passages, he and William engage in a fervent debate over laughter. This discussion highlights William’s stance as an early humanist and liberal theologian, whereas Jorge is conservative and firmly opposed to anything but a strict interpretation of the Bible. Towards the novel's conclusion, it is revealed that Jorge is the true authority in the abbey. He has meticulously worked over the years to restrict access to Aristotle’s lost book on comedy, even going so far as to poison its pages so that anyone who reads it will perish. Jorge believes that the book could lead to the downfall of Christianity, justifying his actions as doing God’s will by eliminating those who would read the book and ultimately destroying the book itself.

In a largely playful homage, Eco models Jorge after Jorge Luis Borges, the renowned Argentine writer. As Eco states in his “Postscript to The Name of the Rose,” “I wanted a blind man who guarded a library... and library plus blind man can only equal Borges, also because debts must be paid.”

Malachi of Hildesheim

Malachi is the chief librarian of the abbey. In this role, he alone knows the precise location of every book in the library and all the entrances and exits to the building. He has unrestricted access to the library and its books, with the authority to prevent others from entering or reading books he considers dangerous. Malachi acts as a gatekeeper, both to the library and to knowledge. He meets his end by reading the poisoned book.

Nicholas of Morimundo

Nicholas is the abbey’s glazier, responsible for the glasswork in the abbey. He is intrigued by William’s glasses and learns to craft a new pair when William’s are stolen.

Remigio of Varagine

Remigio serves as the cellarer of the abbey, responsible for procuring and storing food. He is short, stout, and cheerful, clearly enjoying the perks of his position to indulge himself. Additionally, he trades provisions for sexual favors from peasant women. Remigio was once part of a heretical sect and, under Bernard’s interrogation, confesses to multiple murders and heresy. Consequently, he is sentenced to be burned.

Salvatore

Salvatore is a peculiar and beast-like monk who speaks a mix of various European languages. He finds women for Remigio and was also involved with a heretical cult.

Severinus of Sankt Wendel

Severinus is the abbey’s herbalist, possessing extensive knowledge of and access to various herbs, including toxic ones. He provides Malachi with herbs to induce visions for anyone attempting to enter the library. Unknowingly, he also supplies Jorge with the poison that taints Aristotle’s book on comedy. Severinus meets his end at the hands of Malachi, who kills him to steal Aristotle’s book.

Ubertino of Casale

Ubertino is an elderly Franciscan who has sought refuge at the abbey for years. Many of his followers or associates were considered borderline heretical by the orthodox church, putting Ubertino’s life at risk due to the ongoing debate between the papal legation and the Franciscan brothers. Ubertino's role in the novel is to articulate the Franciscan stance on love and poverty. However, his bond with Adso is somewhat problematic, as several scenes reveal Ubertino’s inappropriate attachment to the young man.

Venantius of Salvermec

Venantius is a young manuscript translator who recognizes Aristotle’s book on comedy due to his knowledge of Greek. He dies from the book’s poison.

William of Baskervilles

William is a Franciscan monk dispatched by the emperor to mediate the debate between the papal legation and the Franciscan order regarding Christ’s poverty. Formerly an inquisitor, William has renounced this role upon realizing that the boundary between heresy and orthodoxy is very thin. Influenced by Roger Bacon’s rational empiricism, William tests his hypotheses through observation rather than relying solely on reason or authoritative texts. Following his mentor, William of Occam, William of Baskervilles is a nominalist who rejects the idea of universals. He believes that only individual things exist and that abstract general concepts exist solely in the mind. For instance, a nominalist would argue that while there are many individual chairs, there is no universal chair from which all individual chairs are derived.

William is a wonderfully intricate character. In some respects, he is clearly inspired by Sherlock Holmes, evident in his name, appearance, and investigative approach. In other aspects, he appears to be a reflection of Eco himself. William often seems like a contemporary semiotician grappling with the constraints of medieval discourse. He is exceptionally intelligent, yet he ultimately solves the mystery of the murders by sheer luck rather than through his investigative techniques.

William contends with his own arrogance and insatiable thirst for knowledge, traits that lead others in the story to their demise. Ironically, it is William's involvement in the case that results in the destruction of Aristotle's book on comedy, the very object of his quest.