[Keeper of Dol Guldur]

Dwarves are like vikings, but were a viking nordic legend in the first place, which was easily transfused into the world of Tolkien's English Mythology. After all, the Celtic, Nordic and early British were all of the same origins, they just went their separate ways at very different times.

I think the elves were based more on scandinavian culture, of course in a high and classy way, and with some Welsh influence, unlike the Rohirrim who were certainly totally Scandinavian in influence.