Dreadwalkers

The Dreadwalkers, more colloquially called “Savages”, “Cave Runners,” or simply “Raiders” are a collection of mysterious ancestries which live deep underground. The oldest records from a great Dwemer empire do not mention the Dreadwalkes at all, until they suddenly appear in the records and destroy the empire. This was the incidence which names this era the Age of Terror, and what gives these beings their name.

The Dreadwalkers maintained their reputation over now-thousands of years. Their constant raiding of the surface is what kept the surface peoples from rising again for nearly three thousand years, and even now most people are aware that the current civilizations live in the shadow of these old Dwemer kingdoms. Their constant raiding has become slower, and there is fervent debate if this is a good thing, or a bad thing; It could mean that they're dying off, or it could mean there is conflict below. If they war beneath the surface, does this mean there is greater threat, or coming organization between them? Which would be worse?

In the slowing of their raiding, some few have come to live near the surface, and some of those groups are peaceful. Most aren't, but some are. They've become a constant presence, not always a terrible one, and as such, some oddities arise, such as the very rare Uruk or Goblyn living within a kingdom, or much more common, Half-Uruk and Half-Goblyns. Still rare, and oh so few people tolerate their presence, but they can be found in most cities, even if only one or two.

Lore
The Walkers live far beneath the ground; Old Dwemer records claim their kingdoms were "Three mine-weeks deep", implying several miles, based on how quickly a team of Dwarves can mine downward. Despite this, they are able to journey to the surface-kingdoms quickly and escape just as fast, so many scholars believe that there are outposts close to the surface, which are then connected lower.

Some Walkers have banded together on the surface, and some have attempted to fully join civilization, but both are rare compared to the armies of Illlria's past, and the legions of Dwemer records.

Dread Tongue
The language of the Walkers is a dark and harsh tongue that nobody has fully translated. Even Uruk and Goblyns and such that live in cities speak little of their language, often saying that the language is simply so different that trying to translate is impossible. Attempts have been made though, and some people have learned the Dread Tongue, enough to speak to and understand local Walkers, at least. Though a writing system exists, it isn't fully understood, in part because of conflicting accounts. The going theory is that Walkers in different areas actually have distinct, but related languages and writing systems, and Walkers tend to travel far before settling down. They all seem to agree on using sounds that are very throat and lips heavy, with few sounds related to the tongue or teeth, as with most other language.

As such, the Dread Tongue remains a mystery, even with speakers and limited translators.

Walkers
There are five known types of Dreadwalker, though the relationship between them all is unknown. There are Goblyns, Uruk, Urkali, Thrull, and Ochres, from smallest to largest, and from most to least common. Goblyns are small and green-grey skinned, Uruk are human-sized. Urkai have curling hornes but are quite similar to Uruk.