The Neureni Horde
From Mistipedia
The Neureni Horde invaded Prime Material Barovia from the east through the Svalich Pass in roughly 230 BC. They advanced as far as Vallaki where General-Princess Nicoleta von Zarovich routed them after a three-month. They held Barovian land for a total of seven months. The word neuri lingers on in Balok to this day and signifies either werewolf or shapechanging wizard.
See: Blood of Mazonn
References
Gazetteer I, p 16.
