Board Thread:Speculation House/@comment-14138255-20160807005311/@comment-10390252-20160817095230

There is some indication that human civilisation on Remnant goes through cycles of development, growth and extinction and a die-back to hunter-gatherer barbarism. Remember back in Players and Pieces? The big fight occurred in a ruined city at least as large and sophisticated as Vale; all reduced to ruins like Mountain Glen would millennia later. That was almost certainly a ruin from the previous Cycle to the current one. The cave where the Giant Deathstalker was hiding in The Emerald Forest, Part 2 was a ruin of sorts from an even earlier Cycle.

It is quite possible that this is what Salem meant in the prologue of the first episode about 'darkness' periodically returning; it is possible that RWBY is set during one of the die-back/extinction epochs. Ozpin knows about this and is trying to prevent it. Salem knows it too and she wants to enable it because she regards it as part of the 'natural order' of the world. Indeed, it may be her position that, as in each cycle of growth, humans have ultimately reached higher and higher levels of civilisation and technology, that the die-back is an essential and critical part of human evolution.

However, with Ozpin having evidently rediscovered many of the champions of the previous cycle (especially the Silver-Eyed One), it is just possible that, for the very first time, Cycle will be broken.