Ryouko Hanuki is an energetic dentistry student. She possesses long brown hair, black eyes, and a mole on the bottom left side of her chin. Her typical attire includes a black short-sleeve top, denim hot pants, a gold necklace with a white tooth pendant, gold star earrings, a gold bracer on her right wrist, and red high-heeled shoes. Hanuki exhibits a lively and carefree personality and particularly enjoys drinking alcohol. When intoxicated, she tends to become unrestrained, though she remains aware of this tendency and carefully selects her drinking companions to ensure safety while maintaining her enjoyment. Her social interactions emphasize living in the moment and valuing friendship as a means to navigate life's challenges. She is first encountered accompanying Seitarou Higuchi at a bar in Shijo Kiya. After witnessing the main female character defend herself against Toudou-san, Hanuki invites her to join their nocturnal activities. She participates in gate-crashing strangers' parties and later observes a drinking contest involving the supernatural entity Rihaku. Following the contest, she consumes imitation Denki Bran from Rihaku's cup. This leads to severe illness, identified as the "Ri Haku Cold," making her the initial carrier who spreads the illness throughout the city. The characters in her name reflect aspects of her character: "Ryouko" combines "cool/refreshing" (涼) and "child" (子), while "Hanuki" derives from "feather" (羽) and "perseverance" (貫), symbolizing persistence despite difficulties.