This manga is a definate favorite for me because of two things. The first is that overall this manga is addicting and it's enjoyable. The second is that it is one of the few longer and not completed manga series I actually can read over and over and still not get tired of reading it. Another important factor for making this a sucessful book is the mystery, action, and the horror plot it is based on. The characters are what really gets the story going because the author does not go too indepth with the characters and with the ones that should be more indepth, you learn more about them over the range of the series and little by little you learn more about them, which gives the characters and the plot more of a puzzle like storyline.