(covers information from an alternate timeline)
The tribe was comprised of blood descendants of Worf and Jadzia Dax, and took their name from the House of Mogh, of which Worf was a member. Others with no blood relation who wished to live as Klingons could also join – after proving themselves as worthy, they could take a Klingon name and live among the tribe. The Sons of Mogh lived as warriors and hunters in the outskirts of the main settlement, only crossing paths with others in order to trade. The tribe practiced the ways of the Klingons as first taught to them by Worf in the 2170s.
When the tribe learned that the actions of the Defiant crew (which visited the planet in 2373) could potentially result in their timeline being erased, they asked Worf to kill them so that they could die an honorable death and take their place in Sto-vo-kor. Instead, Worf offered them a challenge - to join the colonists in their toil against time.