Oujisama ni wa Doku ga Aru.

Rizu's childhood friend Souta has always been super cute but also just a little helpless, so she's taken it upon herself to take care of him. Little does she know, that Souta is only a facade! No scheme is too extravagant—Souta will stop at nothing to keep her to himself.

(Source: Kodansha Comics USA)

Included one-shot:
Volume 1: Ayukawa Rena wa Shigo 4-ka (It's Been 4 Days After Rena Ayukawa's Death)