Tawfret

I'm not going to use the template or anything just because it's simply an Earthlike world, though merged with its Hell dimension. The landscape is constantly changing, there are numerous cities controlled by(and some populated with) demons, whether demons with bad intentions or decent ones. Either way the Hellwatchers and other demon slayers intend to slay them, intent on purging the earth of demonkind.

This is a chaotic world, where anything really can happen or exist. Demons, angels(some manage to make it onto the world to fight, though as the planet is considered part of the hell realm now, it makes it difficult), vampires, even dragons all exist on this world, whether they're trying to rule, kill, or just simply live on the earth normally.

The technology is about modern level, with demon slayers generally using modern military weapons in addition to magical equipment. Sometimes even magically enchanted modern weapons.

Addition to the idea of the world constantly shifting: Areas considered holy/protected do not shift like the rest of the world, so sanctuary cities where humans live are fine. Demons are able to do the same thing if they choose to live on earth rather than their own realm, so really it's just abandoned areas or areas full of feral demons that do this. Which is a lot of places after the merge.

Not going to hide this or anything, several demon-controlled cities are directly inspired by DmC Devil May Cry's setting Limbo City. The place is filled with subliminal messages and other things used to control the population of them even despite demon fights happening around them, and the city itself even tries to attack people if they're a significant threat(Such as a Hawke walking in, being detected as an angelic being which warps them into the "true" form of the city)

I just absolutely love the setting of DmC and the game in general is a big influence on Talon as a character.

Figuring out countries

Unsure of name: The country the Tawfret empire is in control of, one of the larger countries
The cursed lands: A large majority of the planet that the demons are in full control of. There are cities alongside ruined areas, but the population is mind controlled into thinking the demons are the "good guys". The seas are entirely owned by the demons as well, which makes naval travel difficult.
Alfheim: The Elven country, mostly stays out of conflict and has the demon invasion under control. Only place where absolutely nothing shifts from the Merging ever. There are demons here, but they're exclusively benevolent ones.
Zharkonus: The Orc country, a massive wartorn island. Years before the merging or even demons were a major threat, they were beaten in a massive war that caused most of the country to be blown up by magical explosives. Attempts are still being made to rebuild, but the current state is a divided nation full of different Orc tribes attempting to take over to rule, which set the whole country back technologically. The place is mostly deserts, with destroyed buildings everywhere. The Tawfret empire stays out of this conflict entirely, but has been known to secretly send war prisoners over here as a form of exile. (Generally inspired by the Mad Max series of movies)