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

And how do corrupted souls create bodies for themselves to become demons?

In the lore of my world, there is no classic Inferno, so these are just bodies for corpse eaters.

Added 10 minutes later
The corpse eaters in my world are closer to folkloric wendigos; they are also creatures of hunger. Corpse eaters eat not only flesh but also some phantom remnants of life force, which gives them the ability to evolve or create new corpse eaters (a new corpse eater emerges from the vomit of a large corpse eater).