The Great War
Created hundreds of years ago, in the last war among the gods, which levelled entire cities with their battles. RR was created by a __ (family, individual, other?) of those disposessed by the war. They roamed from town to town, at first, begging, then to provide a home for more of the homeless as more cities were destroyed. By their nature, they accepted any, and all, regardless of race, class, or religion. After decades of this, they were the size of a small city, and had become true nomads. Their regularity in the cycle became like the seasons, some farmers even timing their harvest at their arrival.