It's as important to note that the Rus were actually viking merchants/raiders. The locals were Slavs, a different culture, and one dominated by the villages the Rus built as trade centers.
(And that the Rus were basically made into the Russian nobility by Gengis Khan.)
I think the Rus were merchants and settlers themselves. The Vikings would pass through and trade with them, and be given hospitality. They weren't so much allies of the Vikings as saying to them if they sail farther there are really big, rich targets.
Genghis Khan did provide for the eventual rise of Russia through supporting the Grand Duchy of Moscow. The Slavs were as much a part of this culture as the Rus or anyone else, though they mainly originate farther southwest around Ukraine and Bulgaria.