Since the beginning of fiction, people have had an idea. The idea of mixing one or more characters together into one being. Gestalt, fusion, amalgam, or any number of other words for the same mean. For when someone mixes things so they come together.

There are many ways to do this. One is merging characters within the same universe. Another is merging characters from different universes. Still another is merging characters from multiple universes. To see the merging of powers, the choice of what gender they are when a male and female merge, to decide if history changes for that character or not, and so on. You don't even have to use a character only once for a fusion, you can use them in multiple fusions if you wish.

So pick your favourite universe, favourite franchise... Select characters and start to fuse them into one or more characters. You have any number of methods for this to happen. From Yet Another Halloween Fiction, to characters like Access, to something original... There is any number of ways for these tales to begin....