Neville, later known by his pseudonym, Navon Du Sandau, was the illegitimate son of Count Corvallis of Cavell Keep and cousin to Owyn. Disinherited, he framed his own death in a wine cellar collapse only to return years later, assuming the role of a handsome and sophisticated travelling merchant, Navon Du Sandau, in order to fulfill his revenge by courting the Count's daughter, his own sister, Ugyne.
It was during these years that he run into the remnants of the Nighthawks, a guild of assassins, hiding in the Cavell Keep area after the purging of their headquarters in Krondor. Initially held for ransom by the assassins, he used an enchanted spyglass to convince the Nighthawks of his magical abilities and eventually rose to become their leader. Aware of the vast tunnel complex below Cavell Keep, which he had used as an escape route from the wine cellar collapse, he caused the fire that burned down the entire Keep in order to establish a secure hideout for his assassins within these tunnels below the ruins.
Neville was uncovered by James and his companions while investigating the poisoning of the Kingdom soldiers at Romney, the evidence of which pointed at Nighthawk involvement. The leader of the assassins perished in combat with James and his death led to further disarray of the already crippled Nighthawks as their infiltration in Northwarden in order to help the moredhel invasion was also revealed.