It's weird that he has only experienced randomly generated aspects of the story so far. Demons and humans having different magic scrolls is something that you would almost certainly have established, but since he was third-rate maybe he didn't idk. The fact that he was the writer of this world has been pretty irrelevant so far despite the fact that it's a fundamental concept of the narrative. Every time something comes up - "oh, I didn't write about this". He couldn't even remember a town to call his hometown. Maybe they should have made him a reader instead.