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

Sareth did free the demons, but they didn't conquer the world; instead, they became, let's say, "aggressive neighbors" to the other factions. With the arrival of the demons in Ashan, the cycles of eclipses ended, and the cycles of the Void began. In short, the demons became Ashan's second-biggest enemy, and the Order of the Void, led by Sandro, rose to the dominant position. I have no idea what the future holds for them. This information comes from Erwan's presentation on Ashan.