"Alloy" (basically we call it Alloy in Sekai as a general term, Mythril is a great Dwarf word for it though) figures into the "pillars" in the following way: It is mined from the depths of Sekai, near the center of the earth. It has amazingly powerful magical properties for a metal - it is strong, can withstand fierce impacts, and can only be molded and played with by magic or great engineering. It is incredibly difficult to mine and to produce - that is why it is never used for smaller things like bullets, swords, or armor: it is far too heavy for these uses and it would cost way too much to make such small items (though, perhaps as the game progresses, certain nations will discover a way to make these items).
I used the word "pillar" as just a visual aide - but it can be any form of support, as long as the settlements are somehow raised above the troposphere.
So, a quick image: settlements above the troposphere for Orcs/Humans mostly, and terraformed ecological ones (often domes), for Elves and Half-Elves, and then mountaintop settlements for Dwarves/Goblins (in ancient mountains that reach high above the troposphere), as well as special "floating islands" (more on this later as I think more about it).
Alloy also works as a repellent of toxic gases caused by the Asteroid. This is why underground there can exist some small settlements/mining colonies/outposts - so yes Dorovel could effectively have Dune-like sietches in their former area. I would love if people played their former city-states/kingdoms and created a history for it.
Here is my current idea, actually:
Humans, Orcs, Elves, and Half-Elves: Must live above the surface on the plated regions.
(sub: Elves and Half-Elves focus on ecology with their settlements - they terraform plates and create massive forests and gardens on them)
(sub: Humans and Orcs focus on creating actually settlements, towns and cities, on the plates)
Dwarves, Goblins: Must either live underground in very perilous settlements, or, can inhabit "floating mountains" - (think of that thing in Chrono Trigger)
(sub: Both races have wide expanses of tunnels and other such settlements underground, that were greatly harmed by the Asteroid- many of these settlements are in the process of moving to the ancient mountains, those that reach above the troposphere, as toxic gases have begun to leak into the mountains through openings, which are now being magically sealed/engineered in a special way - this makes Dwarves and Goblins masters of underground technology and invention, as they are able to devise inventions and ways to keep gas out of the mountain settlements (magical doors, ventilation systems, and a network of regimented routine). But, keep in mind, that these settlements would be sparse, and barely able to survive - the floating mountain engineering feat is what they would really be proud of, creating mountains that are held up above the atmosphere, or inhabiting great magical massive mountains that have existed for a long time that reach above the atmosphere (so Dwarves / Goblins could only be in the "white" areas of the map).
(note1: Obviously there would be great cooperation between Humans/Dwarves and Orcs/Goblins... the Human/Orc settlements above the surface would be aided by any mountain dwellers below, in engineering, construction of support, etc.)
(note2: Some Dwarves and Goblins, obviously, are intermixed with Human / Orc settlements above the surface)
Undead: Not sure yet... but kind of thinking they might be the only race to be able to live on the surface itself... but at a price of constantly being under attack.
lord_joakim, thanks for the enthusiasm. That's awesome. And yeah, some sci-fi/fantasy people could take a look at that could serve as a basis/inspiration: Arcanum, Fallout(kind of), aspects of Bladerunner, Dark City, Chrono Trigger, Final Fantasy VII, Dune, Steamboy, Magic: The Gathering, etc. Tech/society wise we are talking about like mid to late-1800s levels.