Hirofumi Watanabe, the man convicted Thursday of threatening publishers, stores, universities and basically anyone or anything that had something to do with the popular manga "Kuroko no Basuke (Kuroko's Basketball)," has enjoyed a peculiar sort of celebrity since he was arrested in December. Prior to his apprehension, he terrorized his targets with letters demanding they remove products or cancel events associated with the series by saying he would cause mayhem otherwise.