Leonardo da Vinci is a 43-year-old polymath renowned across Italy for his artistic genius, scientific mind, and fashionable charm. Driven by a relentless curiosity about the natural world, he sketches, engineers, and experiments constantly, though he struggles with finishing his artistic commissions. Beneath his glamorous public persona and intellectual detachment, he harbors deep anxieties about his legacy and his place in the world.

Michelangelo Buonarroti is a 24-year-old, fiercely passionate sculptor who views carving marble as a divine calling. Unlike his fashionable rival, he is scruffy, intense, and completely consumed by his physical labor, often working himself to exhaustion. He returns to his native Florence with an overwhelming desire to prove the true worth of sculpture to a society and a family that views it merely as manual labor.

Mona Lisa is the wife of a wealthy Florentine merchant who longs to be recognized for her true, authentic self rather than her societal roles. She possesses a profound capacity for empathy and is the rare person who seemingly understands Leonardo's hidden desires, particularly his dream of human flight.

Niccolò Machiavelli is a pragmatic, highly strategic diplomat working for the Florentine government. He views art, engineering, and alliances purely through the lens of statecraft, prioritizing the survival of Florence above all ethical concerns or artistic passions.

Cesare Borgia is the ruthless, illegitimate son of Pope Alexander VI and the commander of the papal military forces. His bloodthirsty campaigns across the Italian peninsula pose a constant, looming threat to the Republic of Florence, casting a dark shadow over the artists' work.

Salaì is Leonardo's young, handsome assistant and romantic companion who travels with him across Italy. He acts as a grounding, intimately devoted presence in the artist's life, though his fierce protective instincts sometimes clash with Leonardo's intellectual detachment.

Lodovico is the patriarch of the Buonarroti family, a man embittered by his history of financial mismanagement and the family's fall from grace. He vehemently disapproves of Michelangelo's artistic career, viewing sculpture as a lowly, unrespectable trade for a glorified stonemason.

Giovansimone is one of Michelangelo's brothers, a man who struggles with gambling and a combative attitude. He is often at odds with Michelangelo but ultimately shares a bond with him as they handle their family's difficult circumstances in Florence.

Buonarroto is Michelangelo's younger brother, who desperately seeks a stable income by opening a wool shop so he can marry the woman he loves. He is generally more supportive and understanding of Michelangelo than the rest of their immediate family.

Francesco Granacci is an old friend and fellow artist who acts as Michelangelo's most steadfast ally in Florence. He provides practical assistance, manages local politics on Michelangelo's behalf, and consistently encourages the sculptor through his bouts of anxiety.

Piero Soderini is a prominent Florentine political figure who becomes the lifetime head of the city's government. He utilizes public art to foster civic pride and unity, playing a crucial role in managing the rivalry between the city's greatest artists.

The Notary is a strict, former devotee of the austere Friar Savonarola who manages affairs for the Santissima Annunziata friary. He harbors a deep, venomous history with Leonardo, having previously accused him of serious crimes, making their interactions fraught with mutual resentment.

Francesco del Giocondo is a wealthy Florentine silk merchant and Mona Lisa's husband. He is a status-obsessed man who commissions a portrait from Leonardo primarily to feed his own ego and demonstrate his wealth, failing to truly understand his wife.

Giuseppe Vitelli is the supervisor of the Office of the Cathedral Works in Florence. He is a pragmatic administrator responsible for managing the city's artistic commissions and handling the difficult personalities of its famous creators.

Father Bichiellini is the prior of the Santo Spirito parish and an old friend of Michelangelo. Despite the severe legal and spiritual risks in heavily religious Florence, he secretly allows the young sculptor access to the priory morgue to study human anatomy.

Maria is a young woman living in Florence who has captured Buonarroto's heart. Their potential marriage serves as a major driving force for Buonarroto's need for financial stability.

Pope Alexander VI is the wildly corrupt leader of the Catholic Church who utilizes his immense wealth and power to fund the violent military campaigns of his illegitimate son.

Isabella d’Este is the Marchesa of Mantua and a longtime, loyal friend to Leonardo. She provides him refuge from war and deeply desires him to paint her portrait, appreciating both his artistic and scientific mind.

Pope Julius II is the newly elected head of the Catholic Church, rumored to have taken power through ruthless means. His reign brings fresh political anxieties to Florence and the broader Italian peninsula.

Felice della Rovere is the rumored illegitimate daughter of the newly installed Pope Julius II. She wields significant influence and hints at major future commissions for Florence's greatest artists.

Raphael Sanzio is a talented, up-and-coming young painter traveling through Florence to study the works of the great masters. His reverence for both Leonardo and Michelangelo demonstrates the lasting impact of their rivalry on the next generation.