Chikashitsu no Akuma

is a Japanese light novel series written by Taro Achi, with illustrations by Kurito Muto. The series began publication on December 10, 2004 by ASCII Media Works under their Dengeki Bunko publishing imprint.

Synopsis
Childhood friends Takao and Elina are in the second year of junior high school. One day, the two men who repeat fights every time discover a secret basement in an old school building that is no longer in use. A magic square is drawn there, and on the old desk there is a magic book and something that seems to be ... And the devil that appears aims at the lives of the two !? Men and women placed in extreme conditions tend to fall in love-when that story is written by Taro Achi ... You can laugh even with a promise. A little pounding romantic comedy.