Warrens of the Middle Realm
At this point the story has been unfolding on and off for 5 years in two campaigns both run by the same DM. Here are some of the things you won't find in "Warrens"...
1. No elves at all other than Drow, anywhere. Explanation: They're gone. Left a long time ago. Don't look for them.
2. No good dragons at all, anywhere. Explanation: They're gone. Left a long time ago. Don't look for them.
3. Any kind of resurrection magic requires at least 60% of the body and MUST take place no more than 7 days after death. After that you're asking for trouble. Ever read "Pet Sematary"? Explanation: Did I mention the world was in decline?
4. The world has fallen under the care of the Greyhawk Pantheon of gods, but many of them are missing or simply gone. Others are trying to gain access for reasons unknown. Yet others have access to the Middle Realm and don't even want it, most notably Hades, the greek God of the Dead. The celestial beings and their demonic/diabolic counterparts are far more involved than gods seem to be in general.
Here are a few other notables.
1. Psionics and Alchemy rules are my own design. The psionics are based on the old first edition stuff with my own changes and additions and are the exclusive domain of dragons and demons. Alchemy skills in the Players Guide operate as normal with a few exceptions, but are considered a subset of a greater science of Alchemy that is totally untouchable by characters lower than level 20 as 'Alchemist' is considered an epic class. Not to mention that anyone called an 'Alchemist' in this world most likely is part of a very exclusive cabal that runs just about everything. For the best picture of what I have in mind here, google Lezard Valeth.
2. I know I already mentioned that this was a low magic world, but there are a few rules here as well. Wizards must be trained in a college setting by numerous professors at great cost. The upshot here for PCs are what we call, "school loans". People playing wizards have should either be rich to start with or have a plan for repayment. Sorcerers are of course a little more numerous as they are self trained, but their draconic blood does not allow for 'good' alignments as there are no good dragons to have been spawned from.
3. The entire world was shaped by two events that are still having their effects in the present. Just about any of your "why?" questions can be traced to these two happenings.
A. The Great Calamity- This happened about 8000 years ago when a thriving culture was obliterated by a massive disaster. In some writings it known as "Day of Burning", in others "The Rain of Colorless Fire". This world is what was left behind.
B. The War of Stars- Learn more about this in the history source material, but in short it was mainly about the Alchemists vs the Gods. No one is sure who really won except perhaps an enigmatic figure called the King of Crows.