When the demons invaded their land, their little cousins, the imps, came along. Many imps stayed behind when the demons were driven out. The imps made small villages in the mushroom forests of this world. It became their new home. Like the demons, the imps were also weakened, robbed of most of their magic powers by the protection crystal. The Raanaar accepted their new neighbors as their servants, and although the imps were not treated badly, they were far from being truly free.
Taken from "facts about the Raanaar"
