RTF is a global modification that replaces all towns in the game.

in general, it's unclear whether a demon can actually rule; in the sixth game, all the heroes seem to be former residents of Ashan, and this is needed so that they can better adapt to Ashan and use demonic abilities; who the ruler is – is unknown; the demon lords, like Urgash, seem to be created from obsidian.

Added 41 seconds ago

The art of demons in the sixth game also features a worm, so it is likely that this is a species, but due to its specificity, it is used for unusual purposes: to dig tunnels for demon armies, to break down city walls, or even entire cities; the size of the worm determines this. And, of course, for hellish fishing.

It's scary to imagine what kind of fish they catch...

Added 2 minutes ago
another question about Dark Messiah: could someone else have fulfilled the prophecy? for example, an orc?