Girl rapes shota in the end of the first episode.
How much more of a FUCKING plot can it be? It's not as if she could possess him and start masturbating furiously with a ring of fireballs spinning round and round the dick, the extra warmth and heat fuelling his erotic fury as he+she pumps faster and harder and eventually launching the ring of fireballs in a spiral tornado of a never-ending flaming fury, resulting in the school becoming one-story shorter than it used to be. Then he could go into a mindfuck-trance where all of the horrible secrets or the netherworld are transmitted to him through the connection he has with Chizuru and after seeing all of the demons and monsters, he goes on a killing spree to the demon world and starts destroying everything in sight but they would just keep on coming and coming, so he has to pump harder and masturbate more so that he can keep the demons at bay.
Then, a few episodes in, Chizuru breaks free of his mind-grip he had on her soul and tries to reason with him with stuff like "KOUTA-KUN!! NANI O SHITTEIRU?!!?! YAMETE~~" but all the kid would do is scream "BUT I HAVE TO KILL THE DEMONS!!" and then she would tell him "No, Kouta-kun, you are the demons."
And then Kouta-kun would become a zombie.