The Midnight Marshes Geographic Location in Kelbonnar | World Anvil

The Midnight Marshes

Located in the south east of the Upper Underdark, the Midnight Marshes are a vast extent of subterranean wetland and lakes, known for the thick mists that regularly roll off its waters, the large supplies of Black Bog Oak and the supernatural events that are regularly reported in its borders by the loggers from the town of Tenore that lies within its borders.


The Midnight Marshes sprawls across the south-east of the Upper Underdark and is a complex network of marshland, rivers, lakes and water saturated soil, much of which is carpeted by a variety of different fungus including the tree-like Black Bog Oaks. It is incredibly hard of navigate through, not just because so much of the land looks very similar, but also because it is pockmarked with pools of mud that act like quicksand, sucking unwary travellers beneath their surface, never to be seen again.   There are numerous ways from the Midnight Marshes down into the Middle Underdark, exiting into the area around the Lake of Tears. Many of these tunnels are actually subterranean rivers, which emerge in the ceiling of the Middle Underdark, forming waterfalls that fall directly into the waters of the Lake of Tears below.     Despite these riverine tunnels between the two layers, the Midnight Marshes are in no danger of drying out. Hundreds of rivers, streams and rivulets from the surface world feed the marshes, their waters making the area permanently damp and cold.

Localized Phenomena

The Midnight Marshes are one of the only places in the Underdark where mist is known to regularly occur. Scientifically, the occurrence of mist in the Upper and Middle should be very rare, as it is normally caused by moist warm air suddenly cooling, something that technically doesn’t really happen in the near permanently damp, cold air of the Marshes. It is instead thought that the Midnight Marshes are a place that is naturally strong with arcane energy, which is what causes the mists to appear.   Regardless of what causes them, the mists that hang over the Midnight Marshes are incredibly dangerous, as they appear suddenly, without warning, and can very quickly make travellers through the region lose their bearings. Many of those that brave the interior of the Marshes have been found dead, often drowned in pools of water that they could not get out of, having been led astray by the vision choking mists.  

Folklore & Mythology

    Numerous stories have emerged about the Midnight Marshes, most of which originate from the town of Tenore on its northern border, whose inhabitants regularly travel into its interior to harvest Black Bog Oak. Often these stories revolve around strange, half hidden humanoids, or floating orbs of light trying to lead people deeper into the Marshes, often attempting to lead them astray, away from the known safe routes through the mire. Most of Tenore’s families know of people close to them who travelled into the Midnight Marshes, to never be seen again. The residents of Tenore believe that the Midnight Marshes are haunted, some believe by the spirits of the dead, some by malign fey creatures and some both.

Natural Resources

The best known resource and export from the area of the Midnight Marshes is Black Bog Oak, a large fungus that thrives in the marshes damp conditions and which has evolved to be remarkably like the oak trees that one would find on the surface world of Kelbonnar’s Material Plane. Loggers from the town of Tenore make regular trips deep into the Midnight Marshes, looking for the largest specimens to cut down and drag back to the town for processing into planks or other goods for which one would normally use wood. The people of Tenore, however are highly aware of their dependence on Black Bog Oaks, which means that they also go out of their way to establish and tend to new groves of the fungal tree, to ensure that their livelihoods can continue.   Fish are also present in the marshes in plentiful numbers and they are a key food source for the people of Tenore and the other humanoids and creatures that call the Midnight Marshes home. Numerous species of edible fungi, moss and lichen also grow in the marshes, which further add to the resources at the bottom of the Marshes’ food chain.
Wetland / Swamp
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