I am going to rewatch all of the ShB (and Crystal Tower) cutscenes before I join the discussion, but there was one thing, that I didn't quite understand. The Warriors of Light of the first shard caused the flood of light by striking down someone called the "Shadow King" (I don't know how it was called in english, sorry), which was probably an Ascian.

How does striking down an Ascian cause a flood of light? Are Ascians something like a dark pole that are necessary to balance things out? Does a flood of light automatically emerge, if there is nothing that causes darkness/chaos anymore? Was this all part of the Ascians plan?