Gwyn ap Nudd
: GWIN ahp Nið (or Nüð)* (ð=th in "leather")
gwyn: "white" but with the connotations of "fair," and "blessed" or "holy."
ap: "son of"
nudd: "fog" "mist"
Son of the war god Nudd/Lludd. King of the Fairies, Lord of the Otherworld (identified with Avalon/Glastonbury) or Underworld (identified with Annwfn/Ufferin), leader of the Wild Hunt; a psychopomp. He battles every Beltane with Gwythyr ap Greidal for the hand of Creiddylad/Cordelia, who may or may not be his sister. He aided King Arthur in the hunt for the Twrch Trwyth in "Culhwch and Olwen," and Gwyddno Garanhir in the poem "Mi a Wum," where he identifies himself with the figure Death. He is essentially the Welsh Angel of Death, called "Gwyn the Hunter" in The Chronicles of Prydain, and is also identified with Herne the Hunter in other places.
He may also be identified with Fionn macCumhil; both names mean white/fair/blessed, and both are leaders of a Wild Hunt; both battle for the daughter of the king; both have spectral hounds (Gwyn's are called the Cwn Annwn, also called the Gabriel Hounds.
According to a Latin manuscript, "soothsayers" would repeat the following "to the king of Spirits, and to his queen"--
"Gwyn ap Nudd, you whow are yonder in the forest, for love of your mate, permit us to enter your dwelling."
* Thanks, Gritchka
, for the correction in pronounciation. :)