Many years ago, on the nights of the Full moon, a great evil was said to have ruptured chaos across the lands. Humans and Demons alike were scared to step foot outside their homes at night until finally they could no longer take it. A demon by the name of Kazuhiko, and his wife Tsukiko, finally stood forward and trapped the evil inside of the moon in the sky.

But every full moon, the seal would grow weak, resulting in the chance of the evil to break free and wreak havoc even more. Kazuhiko and the others created an idea to keep the evil contained but there was to be a sacrifice. Only the song of Purity could keep the evil imprisoned in the moon and so instruments were crafted from the purest of elements and Kazuhiko took his family with him into the sky, their new home to be the cell of the evil they were tasked to keep imprisoned.

The tales of them, and the reason, have long been lost except by few that still walked across the earth. Until, after nearly 100 years, the family returned to the soil of the word beneath their home. The family thought they would be seen as normal but the family was considered evil and outcasts on both the side of the humans and the other demons.

The actions they received infuriated the father and the daughter as the son didn't seem to care of what were thought of them. The mother though…the mother found herself ensnared in a romance between herself and a human king that resulted in a set of twin daughters. It also caused the destruction of its castle, its inhabitants, and the mother and both fathers, leaving the four children alone in the world.