Find the rule that changes the story

Look for a concrete premise: an inherited power, a changed timeline, an unusual bond, or a concealed identity. Consider what that rule allows the protagonist to do and what it costs them. A royal setting alone does not establish a fantasy world, so check the synopsis rather than assuming every palace story includes magic.

Are fantasy and supernatural the same category?

They overlap, but emphasize different things. Fantasy can build an imagined social order or power system. Supernatural stories often place something uncanny inside an otherwise recognizable world. A title may belong to both collections without creating a second drama page.