What I mean is books that have characters live in settings that are, in-universe, fictional in some way or the like. I don’t mean books that have adaptations in other mediums
Preferably the story has at least one of the following:
the world has its own laws of physics;
shows how the world works;
explores the setting’s implications;
explores how it affects characters; or
the world is under threat.
Thanks for your help👍