Fabrizio is a twelve-year-old servant boy who lives in Pergamontio with his master, Mangus. His hand-me-down clothes and a rope belt mark his humble station in life. Deeply loyal and somewhat superstitious, he hopes his deck of tarot cards will divine a safe future for his household. He accompanies Mangus to the castello, determined to protect the older man at all costs.

Mangus is a former magician living under house arrest in Pergamontio after barely escaping execution ten months prior. He has publicly renounced magic, dedicating his life to philosophy and reason to secure his safety. When called upon by the king to exorcise a ghost, he finds his life in danger again, as he refuses to pretend to use magic or indulge royal superstitions.

Princess Teresina is the ten-year-old daughter of King Claudio and Queen Jovanna. She bears a strong physical resemblance to her mother but maintains a still, rigid demeanor. She claims to be tormented by a terrifying ghost that haunts the corridors outside the castello chapel, driving the central conflict as she begs the arriving magician to confirm the apparition is real.

Count Scarazoni is King Claudio's right-hand advisor, an ambitious man who wears a Toledo steel dagger at his hip. He exercises heavy influence over the king and the entire castello. He pushes to marry Princess Teresina to secure a path to the throne and views the alleged ghost haunting as a frustrating obstacle to his political maneuvers.

Queen Jovanna is the mother of Prince Lorenzo and Princess Teresina. Because she hails from a distant kingdom, she is treated as a foreigner by the local populace and feels she lacks true influence in Pergamontio. She expresses deep concern over her daughter's mental state regarding the ghost sightings and tasks the young servant boy with gathering information.

King Claudio is the ruler of Pergamontio and holds absolute power over the lives of his subjects. Superstitious and easily influenced by those around him, he relies heavily on his chief advisor to rule the kingdom. He expects unquestioning obedience and summons an exiled magician under the threat of death to cure his daughter's supernatural ailment.

Prince Lorenzo is the brother of Princess Teresina and heir to the throne of Pergamontio. He is noted by the royal court to be absent in Rome on a holy mission, leaving his sister as the immediate heir in his stead. His absence creates a power vacuum that ambitious members of the court attempt to fill.

Sophia is Mangus's wife, living alongside him in near-isolation following his trial ten months ago. She shares his constant anxiety about the king's unpredictable commands and the omnipresent threat of execution hanging over their household.

Signore Addetto serves as the tutor to Princess Teresina within the castello walls. He is politically aligned with the ambitious factions of the court but finds himself frightened by the unexpected complications of the haunting and the arrival of the magician.