This whole thing contains spoilers.
This we know as canon:
1) The Eyes of Utha are placed at the North and South poles.
2) The root of Ahrenthrok's power is the Crystal, which remains potent even after being corrupted and splintered.
3) The power of the Crystal is sufficient to bolster the World Barrier even after the Northern Eye is stolen, even if this is only a temporary solution.
4) Ahrenthrok was originally built by K'ta'Viiri.
5) Andraax is sufficiently intimate with the workings of Ahrenthrok that he deactivated and locked quite a bit of machinery there.
This I speculate:
1) Ahrenthrok was constructed by Utha.
2) The Crystal is a "third eye." It is not equatorial and doesn't happen to be. It's primary role is to regulate the flows between the Northern and Southern eyes.
3) There is a "fourth eye" to be found in the East, directly opposite the Third Eye that fulfills a similar purpose. It is likely very well guarded indeed, else those in the East would have control of it by now.
As always Metallion's speculations fit well within my sense of the setting freeing the Crystal from the influence of the Circle could have a salubrious effect on the whole situation vis-a-vis the stability of the Essaence across Kulthea or an enraged Schrek might destroy it revealing the Soulsword having unimaginable consequences.
Of course Ondoval of all people should realize the importance of the Crystal. However if he's unaware of the Soulsword he may be unaware of the Crystal's true purpose. After all Ondoval's title was not Daenku.
I do believe I stated that the crystal was similar in nature to the Eyes. And yes, Ondoval, while he was an original member of the Circle, might not have been privy to all of its secrets.
Why would the Ahrenthrok crystal be the only one in the western hemisphere ? And why would Utha locate a crystal in the eastern Hemisphere when one of the goals of the Eyes was to keep the K'Taa'Viiri lords of the eastern hemisphere imprisoned ? That would be like locking the prison door but hiding one key inside one of the prison cells, hoping that the inmates would not find it.
I also find it interesting that the Eyes could be accessed from the west. Once again, this is strange when considering their role as the keystones of a prison wall, but it would reinforce the idea that the west is the *outside* of the prison, or, rather, the part of the prison where the wardens are.
I would not be surprised if there were other crystals - even if they had different purposes. In particular, having one somewhere underneath Nexus Island in Iyxia would make sense.
There'd be one in the East for the same reason there are six shards in a lat - that's how the magic works. Probably accessed from the west only because there's a direct connection through the planet itself to the Ahrenthrok Eye.
I don't think there would be others at non-cardinal points because the purpose of the Eyes is to anchor the global structure. More likely that the Illarsiri - and perhaps artifacts from earlier ages that have been lost or sequestered - function through connection to the Four Eyes via the flows.
There'd be one in the East for the same reason there are six shards in a lat - that's how the magic works. Probably accessed from the west only because there's a direct connection through the planet itself to the Ahrenthrok Eye.
That's an interesting idea. Another possibility might be that the 4th crystal is over the eastern hemisphere. Since the presence of the crystals prevents travel into space, it would pretty much place it out of reach of the Essænce Lords on the surface of Kulthea. Whatever orbiting facility it operated from might be reachable or controllable from a location deep under the Ahrenthrok that Ondoval never knew about.
This would have to be reconciled with the Terran presence over the planet, but there are lot of possibilities for doing that.
Still, it is possible that the bodies of either or both were rescued by minions and placed in some kind of advanced regeneration tanks. But healing could take years and if they suffered brain damage, they might not be the same... just a thought.
In one of the ShadowWorld resources, it is mentioned that one of the citadels of the Ahrenreth is housing a coffin containing Kadæna's body.
Doesn't say anything about her head though. :D