Seeing as I dont have gurps, I could only take Forrest at face value on what he said: " [The Head is] Segoth, the son of Wyrd, who the Dark Gods beheaded at the Dawn of Time. GURPS Myth practically tells us this straight out." I didnt know there was any room for interpretation.
Anyway, my biggest problem is this: The Head cannot be a character not mentioned ever, at all, in the Myth series. The Myth series never said Wyrd had a son. The name Segoth was never mentioned. Bungie would not do that to us.
-Ares