DHA Demonzu!

is the ninth volume of the DHA light novel series, written by Rin Yuuki and Illustrated by Marika Tanimura. It was released under the Dengeki Bunko Imprint in September 2007.

Synopsis
In order to somehow restore the "corrupted" light, her childhood friend Ai Shiratori has taken off (in every sense). From the forbidden XX play that scolds the light with a whip in the maid's costume to the radical ○○ play in the bath ...!? Meanwhile, the mysterious phenomenon "Plagues of Egypt" began to cover Chiyojin Ward, where light and love live. In response to that, the seven devil girls started their mysterious actions one after another ...!?

(source: Bookwalker JP - Translated)