A person of Human descent held the position of Count and presided over one of the six Great Houses of Serenno during the Galactic Empire's rule. Not long after the Clone Wars concluded in 19 BBY, the previous leader met his end at the hands of his own offspring, an event orchestrated by Darth Vader who incited the heirs of Serenno's Great Houses to kill their fathers and assume their roles.
During 3 BBY, this Count was present on the airship Windrunner, belonging to House Dooku, for the regency conclave of the Great Houses, a gathering to select a new regent for Bron Dooku. The Count willingly gave up his primary hereditary claim to the regency, and also chose not to support the Empire's preferred candidate, Lord Rodas Borgin of House Borgin, instead favoring Lord Orom Malvern for the role. Amidst these discussions, the airship came under attack from a pirate vessel known as the Bloodskull. Under the command of Vex, who was employed by Rodas Borgin, the pirates tried to abduct Bron Dooku.
After Bron's presumed demise, Orom Malvern was appointed as the new Count of Serenno, with backing from the Great Houses, the new Count Pero Borgin, and the commander of the Imperial fleet.
In Agent of the Empire – Hard Targets 2, Kostanza was mistakenly identified as Bron Dooku's mother; in reality, she was his grandmother.