Popular parlance tends to use the words devil and demon interchangeably (except when Devil is used as a proper noun for the leader of the Fallen) as the minions of Hell and Fallen Angels. D&D (and as a consequence much of gaming) does pretty much the same thing, mostly mutating them into parallel hierarchies of lawful evil and chaotic evil extra-planar beings (the inherent contradiction of a chaotic evil hierarchy mostly ignored).
However, if you look at the bullet points for the City States of the Apocalypse setting they are not the same thing or even parallel things. At least they shouldn’t be even though I fell into that trap with the original. The two relevant points, rewritten to take that into account are (change in bold):
- The world is mostly blasted waste from man’s war with the minions of Hell. The war was a success in that the Fallen were limited in their ability to rule but the world was destroyed in the process.
- Due to man’s disruption of prophecy the world itself may be undermined and denizions of a new underworld are chewing at its foundations, which troubles everyone.
Those denizions of a new underwold were based on the ideas of a first creation from Ken Hite’s GURPS Cabal among other sources. Originally, following Hite, I was going to call these beings quillip. However, I think demons is a better term.
So, some bullet points about devils and demons in the world of the City States:
- Are beings dedicated to Creation and its preservation.
- Are interested in control more than destruction, seeing the later as a means to an end
- By rebellion are cut off from the power of creation itself
- Are great sources of information about creation
- As an example of how the prior two interact: most devils can teach a magic user any spell, but could not create a new one (this is important, as spells are rare and hard to find.
- When the chips are down are more interested in fighting demons (to preserve Creation and the devils’ quest for power) than in allying with them to harm humanity.
- Are members of a hierarchy and have similarities vertically and horizontally within it.
- Are from beyond Creation and consider it at best irrelevant and at worst an affront to them
- Have interests beyond the knowledge of mortals, but generally have little desire for power in Creation. Such power is just a means to their ends.
- As forces of Chaos their agenda quite often is destruction for destruction’s sake (at least as can be discerned by those in Creation)
- Often have knowledge beyond Creation such as how to tap primal chaos (which Creation was built from) but little knowledge within it
- Probably don’t know the spell you’re looking for but can help you create new spells by tapping primal chaos (whose side effects you may not like)
- Are unique (no two demons are the same) and have highly varying (and changing) relationships with each other.
The biggest places I can see this coming into the game early are spell learning and the agendas of certain inhabitants of the yet to be named megadungeon (among other areas).