OMFG AN EVIL PARTY. :O
This will be broken into a few different sections, including Geography, History, Politics, Culture, and Current Events. The content for each section should be easy to guess based on its name. Also, I think that's a good order based on how fundamental the topic is to the environment, but maybe not. It's close enough.
The land is pretty much a habitable area boxed between walls of uninhabitable lands. Treacherous mountain ranges line the land, and last for a number of miles until you would reach either swamps and marshland to the north, or a desolate wasteland to the south. To the east, the mountains continue at various levels of intensity for as long as anyone has tried to travel through them. To the west, however, is a coastline on the Haledar Sea.
The land is separated by a mountain range that extends from the Northern Range (so-called because it's the mountain range to the north!) almost to the Southern Range (guess why it's called that!). There is a considerable gap between this divider and the Southern Range, which provides the two main kingdoms a path through which they are able to conduct trade, among other things. This Central Range, however, is not impassable, and there are a number of crossings which are available to the public, though they are not frequently used because the pathways are still perilous and not recommended for the inexperienced. The Central Range itself is generally considered uninhabitable.
Generally, the climate of both the Eastern and Western Kingdoms is moderate. In the Summer, highs in the areas further away from the various mountain ranges can reach about 105degF, and lows in the Winter can be as low as -20degF in the coldest regions.
Eventually, I'll get off my ass and actually draw a decent map of the land. And then I'll scrap and redraw it probably a few times because it won't be quite right! Oh wellz.
In the beginning, there was a mixture of chemicals that formed a single cell. This amoeba had a velvet top hat and cane with which he pimped his amoeba hos. 'Tis teh truth, so said God. Kinda. Okay, maybe not, but can you think of anything cooler than an amoeba pimp? I can't. Okay, maybe I can, but that's not the point! STOP SIDETRACKING ME!
A lot of this crap is meta-game knowledge. Nobody really knows it, except the people who were directly involved. Please don't abuse it too much. So, way way back when, about 6,000 years before the current time, there was an illithid colony. This colony was a typical illithid colony: there was an Elder Brain, a ton of Mindflayers, and various other types of icky creatures, including slave monsters made entirely of coarse, toughened brain matter. (It took a while to get that gelatinous crap to the point of being able to stand up in a cool breeze, much less being able to lift approximately ten times its bodyweight. Give 'em a break.)
Anyhow, they were cocky bastards back in the day, or, It was (the Elder Brain, as an illithid colony has a single consciousness, generally). It liked to go out hunting humanoids (including orcs and bugbears) regularly. One day, however, that fucker got hit in the face (brain-face) with a rock that some overgrown orc chucked at him. Do you have any idea how hard it is to perform brain surgery on yourself? I'd rather not find out, but this guy did. His entourage of mindflayers worked and worked and worked for as long as they could, but they never managed to save him. Or, more accurately, he never managed to save himself. He died in the forest, his brain-body slowly decomposed and was naturally cleaned away (some raccoon wound up having the largest brain-to-body-mass ratio in the freaking universe for like a day, until he took a crap), and his caravan was destroyed shortly after his death.
Total fucking chaos followed immediately. You see, illithids "communicate" via telepathy through their connection with the Elder Brain. Being a single consciousness, though, they never really had to "communicate" anything. Anything one knew, they all knew. Imagine the buggers from Ender's Game, or how they Borg are supposed to be (but aren't, for some reason).
OMFG I'M FINALLY GOING HOME FROM TEH OFFICE. MORE LATER. MOST LIKELY. COMMENTS WELCOME. YES, I REALIZE I'M IN LOVE WITH MINDFLAYERS. SUE ME.