*Dragons (both Chromatic and Metallic) ruled the world before any other race.
*Races (i.e. Elves, Humans, Dwarves...) were mostly xenophobic. (Elves were rarely seen, but known as the "Scary woodling people that can see you before you hear them.")
*Race alignments were true to their nature according to the MM1~9999999
*TOME OF MAGIC plays a huge role (before it was banned by the first Wizard's guild as "Dark and Forbidden Magic").
This is just some of the things I've come up with so far. I was wondering if anyone would like to contribute something else in a world with no gods (supposedly, aside from Tiamat and Bahamut. But only the Dragons know this.)
Let me know! Until then, thank you ahead of time!
I do recall looking over a story about how Nerull was also supposed to be mortal at some point, although atleast playing out Cuthbert's mortality (or even pre-sainthood) would be interesting.
If at all possible, you could try and incorporate something from Greyhawk's known past, anyway. From what I do recall, it seems that even the celestials and fiends existed before the gods as well. Perhaps the yugoloths (those were the neutral-evil ones, right?) or their predecessors (or whichever came first, friggin' dæmons) could play some small part. Actually, I'm suddenly picturing the dragon race as a whole as some sort of balancing factor between ancient celestials and fiends (despite the dragons own differing alignments), with the epic force, prismatic, and time dragons being top dog.
...hmm, maybe I should borrow some of this.
*yoink*