Thurgen

Thurgen are the dwellers of the deep. They consume layers of the earth not even dwarven mines reach. They are part of the lowest life-forms in the hierarchy of races.

The word thurgen is an allegoric translation of the Kronzregi word merani. Kronzregi merchants were the first humans to learn about the thurgen, from dwarves who were unfortunate enough to meet them. Merani in turn is a wordplay on the Old Kronzregi expression remi banas, literally meaning cave terror. The dwarves call thurgen Op-Uka-Uk, which roughly means the same, but could also mean tearer of stones.

Those who had seen a thurgen describe them as such:

A thurgen is anywhere between ten and a hundred feet long. It moves on its belly like a snail, however, when tunnels are available, it can be about twice as fast as a running human. 

It has a torso and a head section. The torso is broadest at the center and narrows towards the tail. It has very thick, coarse skin, like that of a shark. The head is large and mostly comprises of the mouth and massive teeth, which can be up to eight feet long and three feet wide. The largest thurgen have up to a dozen such teeth in an asymmetrical arrangement around their head. 

The teeth are made of very strong bone-like material and can cleave through the hardest rock. 

The thurgen has no eyes or ears, so it most likely finds its way using some sort of smelling ability.

Thurgen are immune to phyiscal or magical damage. They are practically indestructible. They consume the ground (also anything that gets in their way) and create manny tunnels. Only thurgen are able to locate themselves in their web of tunnels, anybody who gets lost in them can only get out by blind luck. 

Thurgen do not form a society. We do not know what happens when they meet or whether they can communicate with each other. Similarly, there is no information on their ability to procreate. Some say they spawn at a central location buried in a very deep cave. Others say, as they have no natural enemies or predators, that one day the earth will be too small for them and they will come to the surface to consume everything above.

Some elven scientist say that thurgen can travel between the worlds, using secret tunnels, but this theory has not yet been proven.