Well... That was certainly more eventful then I thought it would be. Salem gets really fleshed out as does Oz. In the case of Salem the gods ultimately twisted her by giving and taking away Ozma and then making her immortal and eventually making her utterly alone drove her mad and her attempt to killing herself just ultimately changed her into a monster. I found it really interesting that despite that she and Oz were able to actually come together again and love each other and even having a family of all things. Oz's decision to try and explain everything to her and then betraying her is what caused her to go down the path she now does. He may not have been able to convince her that what they were doing was wrong but turning against her broke what little of love and humanity she had left.
This explains why she seek the relics. With all 4 they can bring the gods back, Salem likely wants to do that to wipe out humanity(?) by bringing them back to see how much conflict there still is. Oz likely knows the only way to destroy Salem is to bring the Gods back as well but he can't do that until humanity is without conflict and is ready to be judged. Do to this hes had to hide the relics from Salem and while she eventually learned where they were hidden (likely from Lionheart if she didn't know already) she couldn't reach them without the Maidens which is why she has Cinder seek out that power (which we already knew).
Speaking of the Maidens... I think the 4 children the pair had are either referenced or directly connected to the maidens. The battle between Oz and Salem leads me to believe that they were killed, what if they inherited part of Oz's curse of reincarnating into other people just without the memories of whom they were before. This goes against the story we were told on how the Maidens came to be and something Ozpin said I think last season that he was the one who created them, in a way I guess he still did but certainly not what I think anyone was suspecting before now. So the 4 Maidens reincarnate and are the only ones capable of using magic like Oz and Salem although we don't know if its more limited then what they were capable of but this was something that all of humanity once could do. Because they are so rare Oz created a system so that each Relic would need a Maiden to get it while also setting up the huntsmen schools above where each was in order to provide even more protection. Not a bad plan I must say.
The only real question I have is what part does Ruby and her Silver eyes play in all this. Her powers are clearly different from the Maiden's so its not the same kind of magic or at least doesn't seem to be. It also seems unlikely its a power from either of the gods so is it something that was developed when humanity began again after the gods wiped them out? Is it a rare power from the time people could wield magic that somehow survived? Is it something even older then that and unrelated to the gods? I'm not even sure we'll get answers on this honestly, with this big info dump though thats the thing that really can't be placed currently.
I thought the episode was good, didn't expect it to go the way it did and I have to say it was pretty well told even if it was literally a 25min lore dump XD It's certainly a lot to take in but it does answer a lot of questions either directly or indirectly. I'm guessing Oz didn't want them to know the truth because finding out Salem is utterly immortal likely would make them give up hope, or finding out that the only way they can kill her is to bring the gods back and have humanity at peace which they are most certainly not. It sounds like something that wouldn't even be possible in a single lifetime let alone several and certainly not while Salem works in the shadows pulling the strings to make things worse. It's hard to want to stand up to that, to fight against such an impossible looking wall.