Hinaichi holds the distinction of being the youngest Vice-Captain in the history of Kanagawa Prefecture’s Vampire Control Division, officially listed as 20 years old in supplemental materials while character profiles cite 19. Her petite frame contrasts with her combat prowess, wielding dual blades with precision during investigations, though occasional impulsive assumptions complicate her work. Burnt-orange hair crowned by a reactive ahoge and sharp lime-green eyes complement her division’s standard uniform. Despite her disciplined exterior, she harbors a soft spot for sweets, particularly homemade cookies crafted by Draluc, whom she treats with uncharacteristic warmth—a lingering echo of a forgotten childhood incident where he shielded her from harm. A childhood aquarium mishap orchestrated by her brother Kazusa left her with an enduring phobia of penguins, compounded by his lifelong habit of pilfering her meals. Exposure to Ydan Ojisan’s Y-beam imprinted the involuntary exclamation “Wee-wee” during emotional distress, paradoxically nullifying vampire hypnosis. Experimental countermeasures by Draus briefly replaced the phrase with “weekend roast.” Additional quirks include blood type A, an emotionally responsive ahoge, and a marked naivety regarding risqué subjects. She covertly resides beneath Ronaldo’s office, though the motive for this arrangement remains undisclosed.