Hussar was a dog that belonged to Bastien Vildenvert. When Bastien went missing during the war, Dune Vildenvert, Bastien's brother, took care of him.
If Geralt helps Dune find Bastien: Hussar helped the men search the battlefield near White Orchard, eventually catching the scent of his owner and led them to an abandoned hut in the nearby woods. There, Bastien was badly wounded but alive, along with a Nilfgaardian soldier named Rhosyn. Hussar, now reunited with his owner, return to the family's farm just east of White Orchard inn.