If you’re not sure what to do with the dero and tero referenced in The Dyatlov Incident, check this post at The Gralien Report out. Micah Hanks covers a quartet of books about the forms of the underworld and its inhabitants through human history, as well as the particular expression that Richard Shaver brought to the public’s attention through the Amazing Stories magazine.
Little or elusive people, extensive realms beneath the surface of Earth and problematic relations between the overworlders and underworlders are long-running tropes in role playing games. Just look at the Dungeons & Dragons‘ recurring setting element, the Underdark, one of the highest profile examples. The Shaver underworld, with its detrimental robots — or “dero” — and the fallen remains of a by-gone civilization that left Earth for a planet with a less harmful sun gives the whole thing a delightful pulp flavor.
The Shaver Mystery has an ancient, lost world to explore beneath the ground, antagonists in the dero, who delight in kidnapping and tormenting surface dwellers and potential allies in the tero, the remnants of the original race below. It’s everything a role playing game needs. From Hanks’ write-up, it sounds like the key books for someone wanting to add them to their arsenal of material would be Caverns, Cauldrons and Concealed Creatures and This Tragic Earth are the best suited as idea vaults. The other two, Pulp Winds and The Pulsifer Saga, are examples of how other authors took Shaver’s ideas and ran with them in their own fictional works.