Aoi Kirishima

Aoi Kirishima is Haruto's older sister, a college student from Tokyo who returns home for student teaching while working toward her teaching license. Despite being the older sibling, she is the less mature of the two: a heavy smoker, extremely lazy and notorious for leaving her room in a mess, often forcing Haruto to handle her chores. She also favors Haruto and Yuzuki as a couple over Haruto and Nanami.