DHA sono san!

is the third volume of the DHA light novel series, written by Rin Yuuki and Illustrated by Yuta Komiya. It was released under the Dengeki Bunko Imprint in September 2005.

Synopsis
Hello, this is Ai Shiratori. Recently, I and Mitsu-kun are here, this, this, this, my lover! Kya! I told you! ...... Oh, I'm sorry. This is this. Recently, I and Mitsu-kun are steadily climbing the stairs to my lover. But Mitsu-kun still seems to be tempted by the seven demon girls to commit "mortal sin", so don't worry. At best, I will protect Mitsu-kun from corruption! With this "angel's arrow"! ……e? After that, make a proper contract, right? Because "contract" means ...

(source: Bookwalker JP - Translated)