Boku No Kirai Na Otouto

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 Shina, who is a chef. But as Kazuya grows older, he becomes more and more distant, leaving Shiina feeling at a loss from the growing distance between them. When Kazuya enters high school he completely changes and even rapes his brother! Shiina is shocked that his little brother violated him and runs away from home.