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

It seems possible, but Kha-Belekh isn't that easy to overthrow. And it's unlikely that a demon wasn't sitting on the infernal throne before him.

Well, I think it's possible with the Claw of Urgash, after all, it's a piece of a god.

Only Sareth could fulfill the prophecy, and no one else.

Yes, I forgot that the game emphasizes that the son of the ruler must free his father, and not a half-demon breaking out of prison.

Added 2 minutes later
The Kurak who decided he was a dark messiah and would rule the world really resonated with me.