Tomodachi no Imouto ga Ore ni dake Uzai

Ooboshi Akiteru has long since abandoned the messy, melodramatic trappings of adolescence in favor of a far simpler creed: efficiency over emotion. He has no interest in romantic entanglements, nor does he crave a sprawling social circle. A single, genuine friendship is all he needs to navigate life, and he guards that carefully constructed fortress of solitude with unwavering resolve. Yet, despite his rigorous attempts to maintain order, one persistent anomaly continues to breach his defenses with infuriating regularity. She is Kohinata Iroha—neither his sibling nor his friend, but the meddlesome little sister of his one and only confidant. An underclassman who seems to run on caffeinated energy drinks rather than blood, she has claimed his bed as her personal territory and his sanity as her favorite plaything. With a teasing lilt, she proposes dates only to mock his predictable shock, employing every flirtatious trick in her arsenal to provoke a reaction. Oblivious to his packed schedule and his obvious exasperation, she remains a constant, buzzing presence in his private space, turning his sanctuary into a stage for her relentless antics. The cruel irony, however, is that Iroha is the envy of the entire student body. She is a top-tier honor student, beloved by teachers and peers alike for her impeccable manners and radiant kindness. To the outside world, she is perfection personified. Yet the moment she steps into Akiteru's room, that polished facade crumbles into something mischievous and unbearably annoying. Surrounded by the jealous glares of boys who would give anything for her attention, Akiteru is left grappling with a single, maddening question: if she can be so angelic to everyone else, why does she insist on being this insufferable only around him?