Thread:TheSecondEdgeOfTheBlade/@comment-30320802-20161025143709/@comment-25726032-20161025220339

Yeah, when it comes to an AU, you're allowed to mess around with the canon characters as you please. Will it always be a great execution? Not always, but that will probably be due to the concept in general, not the fact that canon characters are in it.

And trust me, you can even have your AUs mostly centered around the canon characters too. I have two AUs myself, and they are Undertale: The Revival and Undertale: From the Ashes. The Revival is about a Ninth Human falling down two years after a Flawed Pacifist Route, and the core objective becomes trying to revive Asgore. From the Ashes is about if Asgore went to the Surface when he got the first Human Soul he could get, and a new Second War would be started between him and the Humans. In summary, your AUs can easily have canon characters manipulated to fit the genre. Just make sure you don't make them batshit OP for no reason, and your changes make sense.

Sorry for butting it, but I just wanted to help as well! Like Jaz here said, if you need anything else, just ask!