This is the largest, and most important, river in Calibran. It has its headwaters in the Caribre Mountains, where a number of smaller rivers and streams come together. As it flows through the kingdom's heartlands, there are many towns and small cities built on its banks. It is used as a highway for transportation of people and cargo around Calibran.
Up in the mountains where the Serpent River starts, there are a number of rivers, named and unnamed, that could reasonably claim to be the thin beginnings of the mighty waterway. Just to the north and east of Mil Dundohr, however, is where the Serpent is commonly assumed to begin. All the smaller streams and bodies of water feed into the river in the area, and here it is known as a narrow, fast moving river that can be treacherous to navigate. As it flows down onto the plains, it widens and slows, and is better suited for transporting goods.
In its long course to the sea, it passes through many lands. It divides the Wild Woods in two, passing near the wood elf capitol at Arlathaelas. The city itself can not be seen from the river, and its inhabitants are rarely seen. It then flows south and west, marking the western border of the Fields of Farsalon, before passing through Cathedra Gate meeting the Great Western Ocean.
The history of the Serpent River is the history of the lands it flows through. It has seen many battles, but just as many treaties, agreements, and romances. Most common is the casual passage of tons of cargo, everything from tools and jewelry from Mil Dundohr to wood elven wines.