Tonari no Kemono ga Henai Shitagaru

The responsible Ririka has always helped to take care of her next-door neighbor and childhood friend, Leon — an incredibly handsome boy. Having grown up like siblings, Ririka believes their relationship will stay this way forever. But the truth is that Leon is totally obsessed with Ririka more than anything else in his life. What is the hidden side of Leon like, once you get past his good-looking facade…?

(Source: Noicomi, translated)