The "Doujinshi" refers to the magazines or publications produced by individuals/associations, which are the self-published books, while the Shougyoushi is different from the Doujinshi, it is a kind of book that the publisher pay for the author to write.
In everyday speech, people use the First Person to call himself or the Second Person to call the other person. For example, in English, people only need to use the single expression such as "I" and "You". But do you know that there are a lot of expression for the First Person in Japanese? Then, here, we take anime and comics as the example to introduce to you the varied "I" that can not be expressed in English.