The questions I want EW to answer the most: WHY and HOW was the world sundered?

[kaynide]

...

It does beg the question, if the Ancients triggered the sundering rather than an external entity, what could they have done to cause the star to go out of balance to the point of the aether going crazy?

Based on story beats, I'd guess:

1) This has something to do with the lay lines we're seeing related to the towers. (The ancients have knowledge on how to draw aether from the planet itself)
2) Possibly, this has something to do with the ancients discovering a means of cheating death/reincarnation; does this require huge amounts of aether? Does it involve tampering with the Lifestream? Did the lifesteam..break..with this tampering? (Is this connected to the religious beliefs of the Azim Steppe?)
3) Perhaps the Ascians are themselves actually Primals (Actually, Guardian Forces), having shed their mortal bodies (a la Hades). This would explain their need for huge amounts of aether, possibly draining the planet.
4) It's the Dark Crystal; The Ascians are the Skeksis. The 12 Gods are the Mystics. (I'm 1/2 joking)

...I'm still on Team Lavos, but there are a LOT of ways the story could go, each with amazing potential.