Rough Diamond: Manga Gakkou ni Youkoso

16-year-old Takatsuki Yuuto has been lucky enough to already meet with success in the manga industry. After he wraps up his series, though, he's looking forward to moving away from manga and more fully experiencing high school life. Unfortunately, the day after he's supposedly done with manga, a favor to a fellow author ends up costing him one absence too many to pass his year at school.

Luckily, he has been offered a teaching position at a nearby manga school, though he will be teaching students that are above his age! The head of the school has agreed to help make his attendance problem vanish, since his grades were otherwise fine. Everything will work out, except that Yuuto does not get to leave the world of manga. To make things even more complicated, he has also run into the ghost of a manga author named Tennouji Akira, a young girl that only he can see, and she is now following him around! Will Yuuto be able to handle the new turns his life is taking?

(Source: MangaHelpers)