The Greytooth Clan is a clan of dragonborn who, during the second age, came into the patronage of a grey dragon named Havanth. Under this dragon's tutelage the Greytooth clan became powerful and united the main five dragonborn clans into one powerful clan. Although most clans united peacefully and happily, there were some who resisted. After a short but bloody struggle the Greytooth came out on top and united the dragonborn in to new empire, Arkhosia, thus starting the third age.
Although in the days of Havanth the clan practiced the primal ways, once the clans were united they lived in a more metropolitan fasion, and began to view the primal ways as backwards and stopped practicing them.