Derluskan

The Derluskans were a group that invaded the valley now known as Barovia prior to Strahd's conquest. Derlusk is a name familiar to our heroes, being one of the largest cities in the Border Kingdoms of Faerûn, known for its abundance of bards. However, in the year 200 — well over 1,000 years before present-day Derlusk — the Derluskans were apparently interested in expanding well beyond one city, and it was they who first established the outposts of Vallaki, Krezk, and Berez.
The Derluskan conquest did not last long, however — after 100 years of rule, the expanding empire fell apart due to infighting and civil war, and most of the Derluskans fled for fairer climes, leaving those who remained in the outposts behind to hold off coill cailleacha and dusk elves eager to push back the invaders once and for all.