The Mirrored Fissures Geographic Location in Kelbonnar | World Anvil

The Mirrored Fissures

A region in the north of the Upper Underdark, where the tunnels that make up part of this level of the Underdark are coated with volcanic glass.


A network of tunnels that was once a place where lava coursed through the Upper Underdark, though the lava no longer flows through these tunnels, it left in its wake a thick coating of volcanic glass, which covers the walls, floors and ceilings of the caverns. This glass is smooth to the point of having a mirror sheen, which is what gives the fissures their name, along with the fact that any light source brought into the area is amplified a hundred fold and is bounced from surface to surface, often for miles and miles, and can easily be magnified to a blinding intensity.   What is more, even those who pass through the region who do not need light to navigate through the subterranean tunnels can find themselves confused, or even surprised by the fact that they can see their own reflections projected, above, below and on either side of themselves by the glass walls.   As well as the visual oddities of the Mirrored Fissures, the volcanic glass is so smooth that it is incredibly hard to walk on and all those who pass through the mirrored halls need to pay close attention to their footfalls.

Fauna & Flora

The smooth, mirror sheen surfaces of the fissures make it very hard for any of the flora that habitually resides in the Underdark to gain any foothold in the area, which consequentially means that it is rare to find herbivorous animals in the Mirrored Fissures and those that are found there tend to have wandered into the region and become lost or stuck.   The region is, however a haunt for predators, who use the terrain against prey that they find there, often waiting until curious creatures or determined adventurers enter, before launching their ambushes.

Natural Resources

Theoretically the volcanic glass that makes up the walls, floors and ceilings of the Mirrored Fissures is a valuable resource in its own right, as it is incredibly hard and can be used to make some of the sharpest edged blades known in Kelbonnar. However, the volcanic glass is incredibly brittle and hard to work, meaning that it is very rarely gathered as a commodity in its own right, and unfortunately the glass’ natural tendency to produce sharp edges tends to just injure those trying to travel through the region.
Cave System
Location under

Cover image: by Chris Pyrah


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