I don't know how to write an introduction. The whole classification system shows a kind of vulgar and ordinary psychological trend. Perhaps I can only say that this is a work that is not suitable for games. It is a real work, although it is small in size. All in all, it doesn't have the excitement you want, no porn, no twist. What I want to write about is the depth gained from ordinary things. The only "interesting" thing is the identity of the narrator "I" - an identity that will make you feel cold by the end.