Originally Posted by
Lyth
My suspicion is that Eric completely misread his father, and that Lahabrea's obsession with his work as well as the hemitheos experiments in Pandaemonium were all part of an attempt to bring Athena back to life by binding her soul to Creation magic. The solution would have struck Lahabrea as obvious following the events of the Shadowbringers short story 'Tales from the Shadows: Through His Eyes', in which a wayward soul resists the pull of the underworld by spontaneously binding itself to his own creation, the Phoinix. That was the significance of bringing that same entity in as a boss this tier, an expansion later.
I think that Athena's despair over the matter will be the trigger event for Amaurot's Final Days, much like Khalzahl was for Thavnair, and the 'terrible cry' will turn out to be the sound of her transformation from within the depths of Pandaemonium. We know that Final Days does not physically manifest itself until after the first transformation occurs. Watching her die a second time will probably break Lahabrea, trigger his spiral into madness, and cement an eternal grudge against us. Azem might front the blame and get exiled as a consequence of it. The hemitheos concept will also probably get reused later on, when Elidibus is sacrificed to form Zodiark's heart.
The 'serpent devouring its own tail' is 'Ouroboros'. It's an ancient Egyptian symbol for rebirth, and it likely symbolizes the cyclical nature of the lifestream through birth and death. It may turn out to have a more literal meaning as a 'lifestream primal', but let's assume that it's purely symbolic for now. The wedges probably have more to do with the flow of the lifestream and what's happening to the reflections and the Void.