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

[AlexionSkyllark]

As per the title.

Ever since I first heard about the splitting of the world into the source of its fourteen shards, these questions have been kicking around in my mind non-stop. Was this event intentional? was it an accident? Or an unavoidable consequence of something? What are the SPECIFICS of this event, aetherologically speaking?

Was it really only Hydaelyn that was responsible for the sundering? or did Zodiark also play a part in it? What about the other parties involved, the convocation and Venat's secret sect? Are they also responsible in some more direct way?

So many questions bubbling in my mind, I really would like to hear your take in all this
So what you guys think?