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.
The secret for immortality has been discovered by an eccentric wizard/mad scientist. Its found you need to reapply once a month. As people stop dying, and the birth rate increases exponentially, people are forced into homelessness, because of the need for food reamins the same, and food is not being produced fast enough to feed the undying population. The PCs have to find the creator and kill him, and destroy production, to save the world from undying, unending torture from hungryness.