Intro
What you often see in fanfiction, is a multi-universe fic. A lot of universes thrown together in one big story. You could think of a school with all your favorite characters, your favorite characters of each movie, book and series going to Hogwarts... Disney High has been very popular on Fanfiction.net and AO3. Your favorite disney characters in a modern school, surviving every day things. I've always enjoyed these kind of things.
So today I will cover the multi-universe movies / series / games that I know, and I will tell you why it worked or why not. In some cases, characters really didn't have to be added and were only there for popularity, but I will go into that too.
Remember that this is my own opinion. I could have an opinion you don't agree with and that's fine. I'd love to know what you think yourself. That's what this blog is for. Not just to throw out my opinion, but to learn from you guys as well.