Rain Wild River

The disputed western border of Chalced. Once known as the Serpent River. In the Six Duchies it is called Rain River.

The river's water is highly caustic. Usually it is dangerous enough to slowly dissolve wood or leather, but in the aftermath of quakes, the corrosiveness increases dramatically. The water runs white and can eat swiftly through flesh.

The liveships are the only known vessels that can reliably survive the corrosive waters. However, there are old, small boats in Frengong, the buried Elderling city in Trehaug, that have an unknown metal casing the wood. That boat lasts longer than plain wood even if it is incredibly old. There are also 'thick boats' that refer to a boat made to last 10 or more days. They are hollowed out from green tree trunks, taken out the river, and sometimes urinated on to make them last longer as that seems to neutralize the water's effect.