Boku no Kirai na Otouto
僕のキライな弟 ; 我讨厌的弟弟 ; Boku no Kirai na Ototo
Author/ artist: KAMO Nabako
When their parents remarried, Shiina gained a little stepbrother 5 years his junior, Kazuya. Kazuya is a picky eater and only eats the food prepared by Shiina, who is a chef.
But as Kazuya grows older, he became more and more distant, leaving Shiina feeling at a loss from the growing distance between them.
When Kazuya enters high school he completely change and even rape his brother!
Shiina is shocked that is little brother violated him and runs away from home.