Waterwaifs were one of the more common varieties of waif found in the Nightwoods. Like all waifs, they possessed the ability to communicate silently via telepathy. They had scaly green skin and, like copperwaifs and greywaifs, had barbels hanging from around their mouths. They were closely related to blackwaifs, and lived near running water in the Nightwoods.
Waterwaifs had very different names to other kinds of waif. Their names were usually made up of a tree-related word and a word relating to aquatic life.