Draugr

A typical appearance of a draugr is that of a decayed and embalmed walking corpse, fully clad in armor and behaving like a living being.

"It is said that the halls of our Ancestral Tomb is inhabited by the walking dead; mummified Blackgards who have been disturbed from their slumber by daring invaders. "

―Trevyr Blackgard

The Draugr, known during the Great War as Asterion's Offspring, were a type of undead that famously appear in Bordermen folklore. According to legend, a draugr is a reanimated corpse of a, preferably mummified, Borderman who returns from the dead to haunt their burial crypts in search of intruders. Like wights, draugr were part of the White Walkers' army of the dead.

It is believed that draugr are bordermen who, for whatever reason, were denied access to the Eternal Grounds. As a result, they have returned to their decaying corpses once again to wreak havoc in retaliation for their denied entrance into the afterlife. Therefore, it is strongly believed that, in contrast to wights, draugr are sentient and capable of thought and speech, and possess a culture of their own.

The myth of the Draugr are later confirmed to be true as all of the dead of the Blackgard Ancestral Tomb arose after the White Walkers' breach of Eastwatch-by-the-Sea. During the Great War, the Draugr were led by Asterion, House Blackgard's founder. It is currently unknown if more Draugr had spawned in the Ashlands, as apparently only Asterion was able to raise them.

Because of the fact that dead Bordermen undergo clandestine mummification rituals, this prevents them from becoming wights in a conventional way. Instead, a corpse has to be raised by another, more powerful Draugr in order to successfully return. It is widely believed that because of this very reason, the Draugr had come form a caste-like system in which the "one who has come first" (in case of the Great War; Asterion), was viewed as the universal king of the Draugr. It's still unknown how the "first draugr" came to be resurrected, but presumably it originated from the Night King's growing influence after successfully breaching the Wall.