Fudatsuki no Kyouko-chan (Vertical Official Colored)

Fudatsuki Kenji is known in his school for two things: for being a delinquent and a siscon. He constantly follows his little sister Kyoko around, fixing her giant ribbon, and chasing off any boys who might be interested in her. However, the truth is much stranger than what people believe: he doesn't actually have a crush on his sister. In fact, he likes Hibino, the only girl in his class who isn't afraid of him.