No matter how you deny it, we human are not the only existence alive on this vast universe, no let it be smaller maybe just in this vast earth.  No Even in this country, or even around your neighborhood, we human not the only living being exist. NO! Even the one who stay at your own bedroom are not YOU alone. Lets accept it. Because, these supranatural event actually have their own rule and law, their etiquete, their habit, and furthermore, their purpose for existing. It is just that, the main character are someone who actually don't want to get involved in it yet ended forced to.