Bergsra are common enemies that can be encountered in Svartalfheim. There is a more-powerful counterpart called the Bergsra Mother, in which they can spawn in wretches.
Norse Mythology
The Bergsrå, known as Bergakungen (Mountain King), Bergatrollet (Mountain Troll), and in Scandinavian folklore as Mountain Rå, was a mythical creature that appeared in Norse Mythology, in which it could be masculine or feminine. It lived in the mountain with a court of relatives and sometimes surrounded by Trolls. There is a common phenomena in which the Bergsrå would trick people into their home in the mountain and become bergtagen (literary: "taken into the mountain").