R-15

According to Kadokawa, an OVA of R-15 will be bundled with the tenth volume of the novel.

Iwaki Tomonori is an average 15-year-old boy who likes older women. He happens to have a crush on his teacher, but soon thereafter, learns she has become engaged. He heads home brokenhearted, only to find a 12-year-old girl named Rizel at his home, who he learns the Japanese government has married him to against his will. Furthermore, he learns Rizel is no ordinary girl; she is a biochemically engineered human, and her creators (her "papa"s, as they are often referred to) promise to waive multiple bills of Iwaki's parents in exchange to be allowed to stay at their house, and thus Iwaki's life with Rizel begins.

16-year old Keisuke Saji loves to fantasize about young beautiful women. He hopes to land the object of his affection, Koizumi Akira. However, Koizumi hates Saji (as well as all men) to the point of assault. While most guys take Koizumi's cold shoulder as a hint, Saji pursues head-on without having rejection faze him.

The story is set at Myoujou Academy, a private girls' boarding school. The 10th year's Kurogumi class has 12 assassins with their sights on one target, Haru Ichinose. Tokaku Azuma is a recent transfer student who is also targeting Ichinose, but she gradually develops feelings for Ichinose.