One thing no one has yet pointed out (to my notice - I am no veteran, and I am frequently away for long periods...) is that it is not completely certain that the Head is at all evil, or that it ever did betray the Nine: All we know is that Alric was against it. Alric would have had reason to have been angry at the Head; after all, it aws the Head which sent him off into the Desert on his unfortunate mission... I probably wasn't omniscient, it just knew more than most about most. Therefore it could not know that Balor would get to the Armour before Alric. Alric was a bit funny anyway after his 'Desert Incident', and I postulise that he attacked the Head out of spite and perhaps a touch of ambition, as the Head was after all 'above him' in the Heirarchy of things. Those who supported the Head were doing so out of loyalty, not brainwashing.
Alric is no 'supreme Good', he sacrificed almost his entire army at one time and sent the rest to their doom in the Explosion at the Devoid.
I still don't know where the Head sodded off to afterwards, though... probably went off to sulk with hurt feelings...
Da Pacifist