Considering how Koa normally behaves in a Satou Kibi doujin, it probably worked, and she just doesn't realize it, since her perspective changed along with her attitude.
"Fufufu. See what a terrible demon I am, now? I will take my time off, and CONTRIBUTE CHARITABLY TO ORPHANS! Quake before the sheer depths of my depravity!"
A type of magic...or more like a brainwashing device... that takes a demon or some such that's committed wrongdoing and corrects them from within by sealing them away for a period of time.Wow......so full of books...!Scary...The demon rehabilitation program.And you were bound within this book too.I was nearly in danger of having my nature improved...I thought I'd been bitten by the demon of the book, and I ended up shut within it...Hmm...So when I touched the book, it reacted to me and attacked...That's right!!So the book was protecting the seal using the magical creatures dwelling inside of it?