In a similar way, it was determined-through-play in our 4e setting that it's currently fashionable for young ladies of means to wear jewelry made of extraordinarily flammable magnesium.
When I read some of your posts, I can't help feeling that my game takes fantasy far too seriously!
The trick is writing down the details you invent on the fly so you can refer to them later and come off like some hotshot god of continuity!
Too often, I rely on the assumption that if it's really important then the players will have written it down.
That used to work, too, but my best note-taking players have moved to England. Also, with DDI the players reprint their character sheets too often, and lose their notes.
Thus does my game achieve a verisimiludinous representation of the foibles of human memory and grasp upon historical events!
<snip discussion of gameworld creation>
Thanks for that. That's interesting.
I tend to use commerically created worlds - Greyhawk, Kara-Tur, Points of Light - and so have some basic questions like the outline of history, and religion and culture, settled for me. This also helps with the fiction/rules integration.
In the case of Greyhawk and Kara-Tur, shared genre conventions help me and the players get on the same page as to what the game will be about. In the case of Points of Light genre conventions play a role, but I also think the PHB does a good job of helping to get everyone on the same page about races, gods etc.
What I try and do before starting the campaign is review the history and myth (and perhaps politics, although politics is becoming increasinly less important in my games, in favour of myth, at least in part because myth survives contact with high level PCs better than politics) and look for points of tension and other sources of dynamism.
In the early stages of the campaign I try and seed this stuff, responding heavily to what the players have built into the background of their PCs. So in the Oriental Adventures game there will be spirits, dragons, daimyo etc. In the PoL game there is Orcus, undead, goblins with strange Bane-worshipping ceremonies, etc.
Then as the players pick up and run with this stuff, the campaign becomes driven more and more by responding to their choices. And I flesh out more of the details of history, myth, recent events by NPCs etc to respond to them and set up new situations.
I think I used to use NPCs - sort of in the way you describe - more than I now do. These days my NPCs tend to be plot devices (there's the werewolf, the amibitious young adventurer who stole an artefact he shouldn't have, etc), or place holders for aspects of myth or history (there's the Vecna worshipper, the Orcus cultist, the apprentice of the greates wizard of Nerath, etc). This hasn't been a deliberate decision - it's just something I've noticed on reflecting on my play. I've been thinking about trying to do a bit more with NPCs, but I find it hard to work with rich NPCs outside an urban setting. And my campaigns haven't been primarily urban since the mid-to-late 1990s.
Anyway, enough about me! Thanks again for the reply. (And sorry, still can't XP you yet.)