Dryads were non-humans who lived in the Wood of the Dryads, north of Nyissa and south of Tolnedra. They were techically "monsters", due to being a race that had no God of their own, but Dryads were likely to take offense at the word.
Dryads were always female and invariably lovely, and captured human males for breeding purposes. Dryads were each bound to a particular oak tree in the wood, and lived as long as their tree. Dryad breeding was tied into the growth of their trees. Due to their close connection to trees, they could communicate with trees and were predicatably not fond of axes or fire in their woods. All dryad names began with a soft "X" sound, including Queen Xantha, X'Nedra (whose name was more commonly spelled "Ce'Nedra"), and her cousing Xera.
One of the great families of the Tolnedran Empire, the Borunes, was closely tied to the dryads through intermarriage. The Dryad trait bred true in Borune females for countless generations. The Imperial Princes Ce'Nedra was of that line.
Dryads experience sexual euphoria when given chocolate, a tactic Belgarath used to his advantage to avoid capture.