Watari-kun no xx ga Houkaisunzen

Watari Naoto has had his share of struggles: his parents died two years ago, and now he and his sister live at his aunt`s house. There, his desire to protect his sister earned him notoriety as "the guy with the sister complex"—which never mattered to him, as his sister always came first. But when Satsuki, a childhood friend-turned-enemy(?), becomes his school mate, Naoto`s ordinary life is thrown ...