Wikipedia
Rhennee
In the World of Greyhawk campaign setting for the Dungeons & Dragons roleplaying game, the Rhennee are one of the major races of humans inhabiting the Flanaess.
The Rhennee are not natives of Oerth, but rather immigrants from a land called Rhop on another world or plane of existence. Believed to have first arrived on Oerth in the Adri Forest, they were driven out by its hostile inhabitants and now inhabit the rivers and lakes of the Flanaess.