Coincidental. The Wild Hunt appears in many cultures, from Germany to the American West; the notion that the Wild Hunt is led by otherworldly elves is most strongly developed in medieval Wales.
From The Black Book of Carmarthen (the speaker is Gwyn ap Nudd, King of the Fairies and leader of the Wild Hunt):
"I have been, I have been where the soldiers of Britain were slain
From the east to the north
I am the escort of the grave.
I have been where the soldiers of Britain were slain.
From the east to the south
I am alive, they in death!"
Watain's lyrics are not close to this tradition and not much to do with the exposition of the Wild Hunt in the games.