There are many evils that exist throughout the world, but the greatest evil of all...is human evil. Greed, lust for power, complete disregard for innocent lives. This is what humans will do when they are desperate or if they think they are in a higher power. Another example is when Humans aim to pray upon the weak or reject a person's love for them. That was what happened to the Piranha Demon/The Eventual Middle Demon Moon #1, Towairaito Kagayaku.

She would eventually find others just like her.

This is the story of the Demon Middle Moons.