I don't know where this is coming from, but I've been thinking about how some fantasy settings - especially D&D clones and subsettings - like to orbit some central monster. The most famous such game is Tunnels & Trolls, in which, at least at the time that I played it, trolls really were the big, scary monster. There's also Ravenloft, which is sometimes described as "D&D with vampires."
So, amuse me. Take a fantasy setting, wrap it around a less common monster, and tell me what you get. I'm looking for something that, like Ravenloft, is thematically coherent. That means no fair just saying "it's like bog-standard D&D fantasy except everyone's really scared of owlbears." You've got to write about why the thing you pick is important and the consequences of that choice.
Alliterating titles are purely optional.