The people of the five-tongued river breed horses descended from the celestial horses of Snowcloud mountain. The horses can walk on the water of the river, but no other river, lake, or sea will hold them. The people live along the northern stretch of the river, from its source at the base of the mountain, and as far south as Icefall ravine, where cold steppe gives way to cold desert.
The river is a road to its people, a natural causeway wider than any built by mortals. The people ride their horses along it, and hitch the horses to large barges that can carry far more cargo than a cart.
Their settlements sit at each fork and curve, long towns and villages whose buildings sit at the water's edge, hiding from the wind in the small river valleys. The nearby lands are used to raise hardy crops, tough enough to survive the cold and the dry, but tough enough to break teeth too. The low hills further out are the pastures for the horses, as well as herds of pale pigs that grow wool and unusually round goats that produce massive volumes of milk.
One of the princes of the coasts sent an envoy hoping to buy some of these water-walking horses. He had hoped to use them against his enemies, reasoning that ships do not expect to have to defend against cavalry. He was most displeased to learn that the horses can only walk on some water, and petitioned his god for celestial horses of his own.