Let's say a setting contained a world like ours. Due to unfortunate circumstances, a large portal to hell opened up in the middle of the planet. Numerous demons spilled out into our reality, overthrowing governments and killing billions of people. These demon hordes were led by devil archons, who settled in various countries and ruled with an iron fist. These nations were essesenti ally turned into torture camps, where humans were enslaved and murdered for the amusement of their overlords.
The only surviving nation would be a powerful theocracy that managed to hold out against the demonic …