This is an important issue.

Authors, Cosplayers, Artists and any sort of creator pour hours of their time into their work. It is heartbreaking to see any of this taken advantage of.

Plagiarism has several forms, there is the obvious literal copy and pasting of people's work, this can be seen in fanfictions and originals, and is equally bad in both cases.

It can also occur exclusively in fanfiction, especially in OC insert stories when the author copies their source material word for work, just changing a few names. I have seen this in Harry Potter's Twin sister stories where the 'author' copies JKR's work of art and replaced Harry's name with the name of their OC, claiming that they use it for 'inspiration'. Don't get me wrong, I use dialogue from the original books in OC stories, but you have to create your own narrative around this, and it is essential that your OC has their own reactions to it.

The final form is when someone rewrites, continues or expands upon another author's story without giving credit or asking permission. This also applies to stealing plots from plot shops. If you want to write a fanfiction about someone else's fanfiction that is fine, just make sure that the creator is okay with you doing this, and remember to credit them! This is also the case if you read another fanfiction and find yourself getting inspired by it and up writing a book that is vaguely similar to that book

I hope this helped!

~Em xx