I hope I don't get in trouble for posting a conspiracy theory.

[Ilsa]

3. I had to look up deros. Found two explanations.

First:

The detrimental robots are a race of diminutive sadists described by Richard Sharpe Shaver to exist underneath the Earth's surface, where they secretely torture the entire Human race with stolen technology of the ancients (mech in Mantong).

Deros reside in the abandoned caverns that Earth's God-races once inhabited, where they've become mutated by both the natural radiation of this planet and the unnatural radiation of neglected ancient technology. The deros use this technology to inflict suffering on all the inhabitants of Earth's surface. Nightmares, common accidents, reports of alien abduction, and insanity are all blamed on the acts of the Deros. Their worst depredations befall any who directly enter their subterranean caves, whether from wandering or abduction, where Humans are ceaselessly killed in the most horrible ways they can conceive and then healed so that the torture may continue. Visions of the Deros' habitat has inspired the Human concept of Hell.

Second:

The deros are evil, degenerate Atlantean dwarves. The regular Atlanteans have long since ascended into space-godhood. But the sadistic deros linger underground to this day, where they subject kidnapped humans (especially women) to horrible tortures.