Akuma no Mikata 666 (5) Monstram Red

is the fifth volume of the Akuma no Mikata 666 light novel series, written by Hisamitsu Ueo and Illustrated by Kaori Fujita. It was released under the Dengeki Bunko Imprint in February 2008.

Synopsis
With the birth of "Not B", Kou Dojima has been deprived of half of the energy required to revive Hina. Knowing his powerlessness, Kou confessed to Maihara Ihana, who supported him, and the two became dating. The problem then becomes the existence of Kou's "official lover", Ihana's older sister, Sakura-she has been abroad and finally returns before the school festival. Kou tries to say goodbye to Sakura because of her Ihana and to give her a damn. Meanwhile, more and more people were having strange experiences in the town. It's as if it's a "harbinger" of something- The popular series, the fifth is a new chapter.

(source: Bookwalker JP - Translated)