The techno-fortress of the Brotherhood of the Land of Nod, and the heart of their organization
The Great King long ago ceased attempting to police the wastelands of his Border Marches, and these debatable lands fell into the hands of petty counts, retired generals, and warlords, who constructed and then abandoned many keeps ripe for plunder.
Pick up a pathology/microbiology book, and add the diseases/syndroms to your game. Your players will freak out.
Coughed at? Diphteria. or tuberculosis?
Drunk from a muddy stream? Or just walked through? Well, let us introduce you to schistosomiasis...
Hit by a stream of energy? Too moch mana is ust like too much radioactivity - perhaps all mages could develop cancer early if too powerful...