Sitting on a 4.7, or Bad, but I honestly think it deserves a 2, horrible. It seems like it COULD HAVE been a good manga, but the author is just not handling the subject material very good. At all. Also, the manga overall is just very, very creepy and terribly written.
So yeah. I'd rate this a 2/10, not worth the read. Instead, just look up a video on it instead or read a full story synopsis. The Anime Man on YouTube actually did a video on this manga, look for it and give it a watch. The title of the video is 'THIS MANGA IS NOT SAFE FOR CHILDREN'.