The Vale of the Sein
While the tributaries fill the land with fertility, the main river Pentos itself becomes fast and cold as it travels through the long Vale of the Sein, properly called a canyon. It rockets through the land and tumbles over the hills, creating many waterfalls along its path. Along these waterfalls are some intrepid villagers who wished to carve a good view for themselves. These people are generally the hardier southern folk.
A Blacksmith's Paradise
Blacksmiths also make their place along this section of the river, indeed, some of the best blacksmiths in the empire, working in adamant or mithril, will create a great smithy atop one of these waterfall islands. The waters in the vale are filled with a hardening sediment, extraordinarily useful in the crafting of weapons, and the fast course of the river means a constant stream of this rich water. The waterfalls are mostly used for magical projects; when a blacksmith not only needs cooling but also force. If a person comes to these blacksmiths with a request, they may be able to attain for themselves one of the finest weapons in the empire -- given time, price, and reputation, naturally.