Seeing
Alien: Covenant yesterday, which (no real spoilers) carries a theme from
Prometheus (and from Frankenstein, ultimately) of lesser beings meddling in creation of life, gave me an idea. I've written
before (and it's sort of baked into the rules in any case, most explicitly in BECMI) about dungeons in D&D being an engine of apotheosis.
What if dungeons didn't just create gods or god-like being? What if they tended to create mad ones? All those weird D&D monsters are waved off as the products of crazy wizards, but maybe they're more specifically the product of crazy, god-level wizards?
In fact, it's possible dungeons weren't originally a tool of apotheosis at all. One made race, the Engineers (or Dungeoneers) did it all on their own. The first dungeons were their laboratories, their three dimensional journals of magical experimentation. A delve into one charts (and recapitulates) their ascension to post-mortaldom--and their descent in madness. A dungeon then, is a living blasphemous tome, recording secrets man was not meant to know.
It goes without saying that probably all life in the campaign world began their. Everything crawled up from the depths, evolving away from its original purpose to its current form. Unless of course, that evolution was the point. The Dungeoneers might have felt they would only have arrived at godhood when they could create beings that could follow in their footsteps--or maybe even challenge their supremacy. Perhaps there's another, higher level game and they need soliders, or experimental subjects, to win it?