Hiyoko is an extremely petite, slender girl with a young appearance. At first sight, Hajime remarks that her voice and her appearance don't give off the air of a high schooler at all. She has long blonde hair that is generally seen tied into thick, curved twin tails with two yellow-green ribbons, a white cat face accessory pinned in the center. She tends to have a rude and foulmouthed personality especially to Mikan Tsuimiki. She has a Growth Spurt but looks younger in years.