kiryuu yuuzuki

She is Mikazuki's older sister, the new teacher at Gakushū Senior High and homeroom teacher to Keita and Miharu. In an earlier chapter, she worked as a clothing store clerk because of her fondness for Western-style clothing. Due to unfortunate timing and being unaware that Keita and his sisters are not blood-related, she mistakenly believes Keita is a deviant who dates multiple girls while engaging in incestuous relationships with his sisters. This misconception excites her, fueling exaggerated ideas about what he and his sisters do at home or with other girls. Believing Miharu is one of the girls Keita is dating, she tries to recruit her for a date to separate him from his sisters. She remains a virgin, but after clearing up misunderstandings, she starts developing feelings for Keita that evolve into a lustful desire. She becomes addicted to the scent of his sweat, practically molesting his P.E. clothes and fantasizing about having sex with him. She is a closet fujoshi (female otaku) with a samurai fetish and enjoys cosplaying. Her passion for otaku goods leads her to spend extravagantly, often leaving her to eat instant noodles. This is also why she no longer lives with her parents, as her mother would disown her if she continued her otaku lifestyle. The sisters see her as a potential threat to Keita's heart, believing he has a fetish for older women and noting her larger bust size. She mistakenly assumes the twins' outfits, designed to catch Keita's attention, mean they share her interests. In the anime, she is already the twins' homeroom teacher before Keita graduates. In the manga, she becomes Keita's girlfriend. (Source: Wikipedia)