Middledark
The Middledark lies between 3 and 10 miles beneath the surface of Faerûn. Most larger cities of drow and duergar are in the Middledark. Other inhabitants include lone aboleths, cloakers, derro, grimlocks, and kuo-toas. A few mind flayer outposts are scattered throughout this level as well.
Settled communities in the Middledark commonly send trade caravans and raiding parties to the surface, or at least up to Upperdark trading centers such as Menzoberranzan and Ooltul. Visitors from the surface are rare and tend to be viewed as potential slaves or food. Caravan travel brings mostly luxuries; staples must be grown locally.
Travel in the Middledark can be difficult. In many cases, it’s simply not possible to go from one place to another because no caves or tunnels lead in the right direction. To overcome this drawback, many of the races that dwell at this depth are prolific portal builders and tunnelers.
Surviving in the Middledark
The Middledark is, at its best, worse than the harshest surface deserts. The DC for any Survival check made in the Middledark automatically increases by 5, even for natives. Wild resources are hard to find, and most of those that do exist have already been placed under guard by someone else.
Glowing fungi and lichens are less common at this depth than they are in the Upperdark. They can be easily cultivated, but most concentrations of them appear in cities, not in the wild. Air tends to be stale, but breathable, though poisonous fumes choke out normal air in a few areas. In many places, water is scarce, and any large supply is well guarded. Creatures living at this depth get most or all of their water from the fluids in other creatures they eat. Food is the most plentiful of the necessities at this depth, but even that becomes an issue at the lower end of the depth range.
Denizens of the Middledark
No alliance is permanent in the Middledark. Some communities maintain wary trading partnerships with others, but it is understood that if one party ever grows stronger than the other, the terms of the partnership will change—perhaps drastically. Even in the most open of Middledark cities, newcomers can expect to be challenged (physically or otherwise) unless they make a pointed display of power upon entry.