Yes, of course!
I have written a draft of one of these before. I did it about Gaster Sans x skeleton reader and made it like a criminal story where they did illegal stuff, running from the cops, escaping prison. Partners in crime basically. But if your talking about an undertale one. Maybe Frisk should also be present and the skeleton should have magic like sans. There will need to be an explanation at one point about where they came from so maybe they were stuck on the surface as a child after the war. They hid good or something like that. I don’t know about what to do with in between events, but near the end, maybe Chara can start attacking everyone and Sans and the skeleton have to find a way to stop them from resetting? That’s a lot, but I hope it sorta helped! Message me if you want any more advice!
