Human beings may never discover that they are not only sharing the city with cats, dogs, insects and birds, but also some "creatures" that cleverly use human appearances to hide among humans. Either out of good intentions or out of malice, they live in this city for survival, for prey, for hobbies... It is an excellent fake hider. In the bustling city, it is him, one of many humans, and even its own kind cannot tell that he is it! (The introduction is the most difficult, I will revise it later)