Noboru Aoi was not happy with Ore no Imouto ga Konnani Kawaii Wake ga Nai ("There's No Way My Sister Is That Cute"). After learning the email address of the light novel's writer, Tsukasa Fushimi, the 32 year-old Aoi sent email after email—over five hundred in total. In them, he threatened the writer's life.
The suspect apparently wrote things like "Die, poser", "I'm going to find out where you live", and "I'm make you regret this." He also supposedly sent an email threatening to slice off Fushimi's head. It seems that Aoi was upset over how the Gothic Lolita character Ruri Goko was portrayed in There's No Way My Sister Is That Cute. Police in Tokyo arrested Aoi for threatening the writer, and the suspect has apparently confessed to authorities.
There's No Way My Sister Is That Cute, which has spawned a manga and two anime, follows a high school student and his 14 year-old sister, who is into magical girl anime and erotic video games.