Kura_Rose said:
No one on here knows that Kura Rose, my OC, is a copyrighted character because they're in a book I've written so all of the rights and the copyright belongs to me. If e621 accepted new tags then I'd put my book's name in the copyright tag.

You can create new tags easily, it just takes a bit of learning on how the reworked tag creation system works. You might wanna look into that, unless you have already and that's why you're posting here.