Chronicles of Khaldun: Crux of Eternity
The oneirobound are lost dreamers, those cursed to wander the Plane of Dreams with little hope of returning to their bodies. (Humans and demihumans in comas or subject to the slumber function of the imprisonment spell often become oneirobound, although it sometimes happens spontaneously.) Being on the border or sleep and waking means that they are especially pliant, given that they are almost-permanently sleepwalking, but that they have great facility with dream-crafting.
Certain oneirobound are able to regain their volition. Such free-willed oneirobound are often called oneirobound lords, and show even greater facility with dream-crafting than their lessers.