Etymological interesting reference, thanks
What i found isnt much and does not fit but can mention it:
- Settlement from the baltic region, early indogermanic, the absorbed. (3000 BC, far too early)
- Turcic/Mogolic wars. Influence to the region not before 1250. (too late)
- Moskovit expansion to the region around 1500. (even later)
- Only thing is left that at this time, is that Samojedic tribes were there at this time (~900), which culture is after Moskovit expansion left more to the north east. But those are like Finnish cousins and cant call them a different culture with a good conscienceness. They were (are) living from reindeer. Those were there, but dont fit to the hypothesis of Njerpez as the game describes it.