From time to time the climate deteriorates and the local tribes get on their ponies and move elsewhere. Shortly after 535AD (beginning of the Dark Ages) they abandoned Siberia and moved to Korea and Japan, neatly conquering both areas and becoming the ruling clique. In Japan these guys are called "The Daimyo" or "The Family".
In an earlier difficult time they'd gone all the way South to India ~ which they conquered sometime about 350 BC, but they were overthrown about 200 AD and "moved back" to Yakutia (They are known as the Sakha).
The people look Asiatic in this area, but they speak a Turcic language. There are videos on the internet about their homeland and you can see the trees and, best of all, the giant bunny rabbits.
This was the same time that Cassiodorus in Europe was reporting strange weather, a blue sun, a dim moon even when full no fruitful summer and no extremely cold winter. Just no change and no growth. A large boloid crash? A major volcanic event? But it did also seem to drive the steppe peoples out of central Asia, conquering or invading both East and West