I personally think that Ozpin/King of Vale decimated the entire army with an ease because he used relics, or if not all at least one of them. Remember, the academies were established after the war by the King with a purpose of protecting them, which begs the question where they were before, and how and when did he get his hands on them. It wouldn't be far fetched supposition.
That’s definitely a possibility. And the more I think about it the more it might make a lot of sense… Okay. So the King of Vale probably DID possess all the relics at the time because otherwise, what? He somehow collected them all before building the schools? Schools specifically designed to protect them? It doesn’t seem likely. But regardless, I can easily buy into the theory that he at least had one.
Which begs the next big question: what are the relics? Qrow says the King decimated the army, “armed only with a sword and his scepter,” which implies that the scepter was used to fight somehow. A scepter could easily be forged to look like a cane instead (as the power of kings dies out/expectations change) and fans have long theorized that Ozpin’s cane is one of the relics.
Running with that then. This is just the sort of red herring that Ozpin would pull. He lets legends develop that the relics are, as Qrow says, within the schools - within “fortresses” - and it’s partly true except that the relic is actually Ozpin’s ‘innocent’ cane/weapon, not something buried in, say, a secret vault (like Amber). Hiding in plain sight and all that. That would throw off anyone looking for the relic within Beacon (as it presumably has with Salem) and let Ozpin keep an eye on it 24/7.
More importantly, it would also mean he’s had a fourth of that unfathomable power to fight with all these years. It would explain how Ozpin was able to so easily best Cinder in the bit of the fight we saw. He was using his relic.
But what if, somehow, he lost the relic during their fight?
Suddenly Ozpin doesn’t have nearly the power he used to and, possessing the Maiden’s power, Cinder is able to kill him. This would also explain how his cane was somehow separated from him and eventually wound up with Qrow.
Presumably Qrow doesn’t realize that the cane is the relic. (Or maybe he does? He certainly hinted that there was more he wasn’t willing to divulge yet). Presumably he still has it on him (I mean, they somehow managed to keep giant sleeping bags on their persons too, so lol). If all this pans out, I wonder how long until Ruby and her gang realize they have a crazy powerful object on their hands…