Every self-respecting castle has its ghost, and Baldu Castle is no exception. Legend has it that the ghost of Ubaldo II Visconti, an important historical figure who lived during the Kingdom of Gallura, wanders around its walls and among its rooms. He held the office of judge of Gallura from 1225 until his death and was buried, according to tradition, in the Basilica of Nostra Signora di Luogosanto. However, it is said that his ghost continues to roam in the vicinity of the castle. According to legend, Ubaldo would appear near the small church of Santo Stefano dressed in Pisan lordly robes typical of the 14th century and would only show himself to the truly believing and worthy.