Pitch
(note: I'm going to crib a couple of ideas from 'Myrinath', the first is to use real world languages other than english in game for setting. "Sons of Nk" may also make an appearance.)
Setting
The world that hosts all guests ("Xenia") has enjoyed centuries of relative peace and order in its Second Age after the long dark winter of chaos and strife of the first age. The world is mostly ordered and sensical. Of course there are occasional wars, calamities, and other problems, but overall things are blessed by the gods of order and light. Unfortunately there are growing rumors that the powers of dark and chaos are stirring as their god seems to be active again and looking for renewed vigor by replacing their chosen avatar in Xenia. This means all sorts of baddies are vying for the position. Many of these are in the long subdued cult of the shadowed hand, worshippers of the Crone of Chaos.
Decisions have consequences
Player characters will have opportunities to help or oppose various groups such as fiefdoms, churches, trade guilds, families, etc. There may not be a clear distinction between who is "good" or "evil", but the decisions may have a "flap of the butterfly's wing" effect on larger social/political machinations. This may be an actual mechanic based on "Reign", but hidden.
Players will not have the opportunity to act as governors or leaders or otherwise be in charge of managing logistics in any way, they are in charge of adventuring and individual encounters. (This note is to preempt concerns about turning this into a management 'game')
Mechanics
Leaning toward 'crunch' with plenty of room for story and explore mode, so probably 5e. All of the core classes, races, equipment, etc. I'd like to limit add on material to maybe 2 or 3 supplements.
Cultures
Xenia has about a half dozen cultures, of which
Groups
Characters, player or otherwise
Nations
and states, fiefdoms, of various levels
Subdued tribes of goblins, kobolds, and other monsters are getting restless and rumor attribute it to some vast shift in the powers of destruction.
Nobility have been resorting to darker plots to settle petty grudges and feed their personal ambition.
Those murmurings are probably just the idle gossip of a land too far removed from the times of strife and without any real problems to deal with.
A primary theme in Xenia is the interplay/competition between order and chaos…