Mizuki Mizushiro is the author behind the Psycome light novels.
Kyousuke Kamiya has only just started to get used to his life in the blood-spattered hellscape that is Purgatorium Remedial Academy and its twisted version of school life. The architect of this series of gruesomely parodic extracurricular activities is the beautiful, charming Saki Shamaya--also known as the "Princess of Murder," a serial killer responsible for twenty-one deaths!
As the final exams for parole draw near, suddenly a transfer student appears! And the newcomer is none other than Kyousuke's little sister, Ayaka Kamiya! Ayaka could not be happier with this reunion but Kyousuke is terrified. What's more, he soon finds out that for the sake of meeting her beloved brother, Ayaka committed attempted murder. Considering Ayaka's mental state, Kyousuke resolves himself to protect her from the pack of killers he calls classmates. But, if someone, let's say Renko, were to find out that Kyousuke's most important 'Ayaka' is his sister, there'll be hell to pay... Facing dangers left and right, Kyousuke will have to be more resourceful than ever to get himself-and his sister-out in one piece.