Akuma no Mikata

is a Japanese light novel series written by Hisamitsu Ueo, with illustrations by Kaori Fujita. The series began publication on February 10, 2002 by ASCII Media Works under their Dengeki Bunko publishing imprint.

Synopsis
Ko Dojima, a high school student with a slightly unusual past who says, "My sister was kidnapped by an alien."

What suddenly appeared to him was a strange (?) Fashion girl who just wrapped a colorful enamel belt around a key point, and was a "self-proclaimed" devil. Furthermore, the "self-proclaimed" devil said, "Your wishes have been fulfilled the day before yesterday. Sensing that magical power, I came. To fulfill the contract and receive the soul."

Can Ko without a contract really prove his innocence !?