Grey King, or Brenin Llywd, is a Lord of the Dark. Perhaps the most powerful, and certainly one of the oldest lords, he lives on the welsh mountain Cader Idris. He is the lord of the milgwn, and none ever dare encroach on his territory... until now.
Coming to Wales in search of peace and recovery, Will is jolted back into his quest for the Light, to wake seven sleepers kept under spells by the Brenin Llywd. He has hidden the Golden Harp, one of the objects of power that the Light Seeks, and it is now the duty of Will and Bran to not only find it, but use it to wake the ancient knights.
The Grey King has other objectives.