Hiyoshi leads the Kanagawa Police Branch's Vampire Countermeasure Division as its captain. He is the older brother of Ronaldo and Himari. Before this role, he was a professional vampire hunter, forced into retirement by injuries from vampire attacks. An initial bite weakened his grip strength, hindering firearm use. A later, more severe bite during a "badger game vampire" incident further prompted his retirement, an event noted as humiliating. Physically, Hiyoshi is short, with silvery-white hair swept back, blue eyes, and a characteristic fake mustache he often misplaces, necessary due to his inability to grow natural facial hair. During his earlier hunter career, specifically shown in Season 2 Episode 6, his appearance differed: his hair was in a low ponytail with one-sided bangs, and he wore a red vampire-hunting outfit akin to Ronaldo's current attire, featuring long brown gloves and a cape, but no hat. Personality-wise, Hiyoshi takes his leadership seriously. However, he shares his brother Ronaldo's inclination towards perverted behavior. His original drive to become a vampire hunter stemmed from a desire for personal glory, the confidence gained through fame, and the pursuit of romantic relationships with women. Despite these flaws, he deeply cares for his siblings, though he struggles with Ronaldo's intense admiration for him. Hiyoshi is also a recurring victim of the parasitic entity Passionate Kiss. He is currently 30 years old.