Ok I know this is like my 3rd topic on this same quest but there's so much here and I'm milking it for all its worth lol
When you do the Orbs of the Blue Depths Quest you have to take on all of these former Black Serpent Knights down in the Chasm. We know from the Requiem quest that these guys are down here to protect the hilichurls but just like the poem at the end of the quest they are also protecting old secrets.
Take these guys for example. They seem to be under the impression that we're working for Celestia. I'd say the "false land" here is a shout out to the false sky because it's weird to suggest that our MC came from some fake world in this way. I'm pretty sure everybody would dismiss it and even if they didn't who is this Haltaf guy to know this thing about us? Meanwhile Serkir just comes out and says it. I think these guys were on youtube watching the theories about the Gnostic Chorus and jumped to conclusions. 
But Haltaf's death line is pretty cool. Partisan heavens. Exactly what Celestia has been. But the why of it we still don't really know.
I feel like this 1 quest actually shows 2 groups of these Shadowy Husk guys. The two from before seem to still be Black Serpent affiliated and a few others talk like them too. But Hyglacg actually sounds like a soldier of the Abyss. I wonder if the Sky Nail will fit into their upside down Venti statue/Osial plan.
He also seems to be talking about the false sky specifically to break it and free everybody from the illusion. But if the Abyss is planning to do that with the Sky Nail it probably won't go well.
The meat of this topic is this guy. Majestic one's dark curse. Of course we know about the curse already. That was the whole point of the Archon Quest. But notice how all of these guys talk about Celestia and anything related to it. I highly doubt they would ever call it "majestic." So who else could they mean?
Remember my theory about Pierro? I doubt he was the only one. What if the curse was actually caused by Rhinedottir?
Just like Buliwyf this guy's words peaked my interest. He accuses us of being companion to "fate" and that we're the "calamity." What could that even mean? Our only companion is of course Paimon so is she this fate and we're the calamity? That could really fit with the old theories about Paimon being the Sustainer but that's already disproven.
I have a feeling this is another case of the unreliable narrator. Just like how we learned that Dainsleif only has a poor opinion of the Archons because he's Khaenrian and they are prejudiced against gods I think Edgetho here is one of the Abyss Husks. Since we're obviously here to bring change to Teyvat the Abyss might believe we're on the wrong side and our interference will bring calamity compared to their belief that they will save it.
One of the reasons why I think these 2 are more important than the rest is because when you fight all these guys only these 2 have support. You fight Edgetho with a regular Husk and Buliwyf is accompanied by 2 Husks. Everybody else is alone.
Finally there's the guy I actually took a screenshot of. Rethel dies with the line like that. We know the Void is the Abyss but based on how Tsumi described it these guys are supposed to be happily snorting the stuff. Meanwhile Rethel here seems to behave like a long-term addict. It feels like the Abyss drug has already consumed him but he's trying to stay civil. Look at the line before we fight him. He's more like a reluctant follower and even tries to get us to not get involved for our own sake. What if it's not even just a drug but something they were forced to absorb and now they're dependent on it? Wouldn't that be nice and depressing.
But at the end of the day would any of this need to be protected? It doesn't really do much for us now right? Khaenri'ah's gone. What happened during its fall already happened. And we already know the Abyss is working against Celestia. So who cares about any of the specific details right?
I think Celestia cares. (I mean us theorycrafters also care but for the sake of just knowing the story the little details don't mean much to the average player.) If my Phanes theory is right all of this stuff didn't happen that long ago. And a part of the Byakuyakoku Collection that we can all agree on is that Celestia was hiding a secret when it buried Enkanomiya. The unified human civilization knows this secret (which is the meat of my Phanes theory) so it stands to reason Phanes also doesn't want its other major actions to become known too. This includes Khaenri'ah's own fall and likely any details about Sal Vindagnyr and the False Sky too.
This suggests that it's all one big conspiracy of Celestia's and what that conspiracy is is something I'll get to later. 
Tips and Tricks from a Super Casual Genshin f2p
Commentaries on Genshin Impact and MiHoYo
PS: And there's also this one.
Shadow? Omnipresent! Hurrgurr Ei's still involved with Celestia errmahgerrd!
No don't get up. I'll show myself out. 
