Hiyosu - 鵯州

Department head in the Research Institute tied to the 12th division. He is a large man with a bulbous head and an extendable eyeball via a crank on his head. He was the one that originally discovered Rukia Kuchiki's unusual gigai. He was also present when the Research Institute discovered that Yammy and Ulquiorra had begun a small invasion on Karakura Town.