Doujinshi

This is amateur manga. Most often it is drawn not by professional artists, but by beginners who publish their own story. The authors choose characters from popular anime, games or other manga as heroes.

Manga doujinshi - what is now mostly understood by the term "doujinshi" - are self-published works, often based on the author's works, that are printed "on their own account" and created for non-commercial distribution. In the case of fan art, it is naturally drawn by fans for fans.