Board Thread:Site Questions/@comment-36877863-20181004140435/@comment-24101790-20181004143613

You're right that they don't own folklore like zombies, werewolves, vampires, etc., but if you are referencing locales like: Gavony, Nevalia, and Devil's Breach or events that occurred in the MtG timeline or relics that hold importance there, then you are using that creator's/creators' intellectual property.

TL;DR: If you use Innistrad as a starting point (generalization: a cursed Gothic-inspired country from the 1700's or so that is infested with vying factions) then it's not likely going to be a violation of our spinoff rules.