It is revealed in the episode "Excalibur", and through interviews with Michelle Ryan, that Nimueh was once the personal witch of the Pendragon family, and was called upon to help Uther's queen conceive.
Det bliver afsløret i afsnittet "Excalibur" og via interviews med Michelle Ryan, at Nimueh engang var Pendragon-familiens personlige heks og var blevet påkaldt for at hjælpe Uthers dronning med at blive frugtbar.