I haven't read any of the books or played myth 3, but it seems to me from all the info i've gathered, that the head is somehow Moagim the previous Leveler, I'm sure he's pissed off about his defeat at the hends of connacht, either that or somehow the head is balor himself and for some odd reason the nine didn't know about this, telling the weakness of shiver as a way to build trust and create a civil war in the west plus his attempt to kill alric in the east. He could have destroyed the legion if a few small details had pulled through.
But we know that Connacht and Balor are the same person, and the head is said to be an Ancient enemy of Balor and balor is known to possibly be the greatest hero of all time. I think most info points to moagim being the head.
