There still isn't too much information on them yet but some of the more recent stuff has got me thinking about another theory on who they are.
Hi guys I am Inotia King a youtuber, redditor and gamer who likes theorizing about the story. I actually cobbled together a list of some of my more important theories with respect to the game Genshin Impact and Star Rail that I have been basing all of my newer theories on. I'll be putting more of those up on Hive along with new stuff but if you're impatient I also archived all my theories here. I hope some of you guys are game theorists too. Let's try to figure out these great games together!
(This topic is long and plenty gets covered so I've added a summary at the end.)
Anyway in the Inversion of Genesis quest we're told by Scara that our sibling "responded to the summoning." That alone doesn't change much. It was already hinted at heavily that the twins coming to Teyvat wasn't by chance.
"This is proof that you came to this world via special means. This is the seal of which only one who has pierced the celestial heights is worthy."
But coupled with the information we got from the Sumeru Archon Quest if all of the Descenders arrived on Teyvat in this same way it would mean they all serve some kind of purpose. So what might that purpose be?
I think no matter what Phanes aka the one that set up the Heavenly Principles will be revealed as the First Descender just like Nahida theorized. Based on my older theories this is because ++Phanes represents an agent of the Imaginary Tree++ with the task of keeping the universe alive. This is further supported by Apep.
But Caribert added a wrinkle to who the Second Descender might be. 
Throughout the quest it was increasingly implied that Khaenri'ah had on more than one occasion looked to the Abyss as an alternative to the Heavenly Principles. It is likely that these actions even caused the Cataclysm. But at the end of the quest Chlothar seems to be suggesting that they also performed a summoning and they believed our sibling was the result of that summoning.
No I don't think our sibling is actually the Abyss or something like that. But the way Chlothar behaves around the Abyss and the Sinner and what we already knew about ++Rhinedottir and her actions++ that led to the Cataclysm I think it makes sense that the Abyss could have "responded to the summoning" too.
++What if the Abyss (actually the Sinner) was summoned by Khaenri'ah long ago?++ Actually what if it was summoned before Khaenri'ah was even a Khaenri'ah?
Ever since the start of the game we've had these ++Artifacts++ that tell the story of the old world during the time of the unified human civilization. Part of it states that the people appointed a priest to appease the angered gods. But instead the priest found something after entering the deep. Could it be he found the Void and in a scene similar to what we saw in Caribert this priest ended up summoning the Sinner? And the Artifacts also state that the priest realized what it was and tried to warn the people but since they had chosen to oppose the gods they ignored the warning. What if that's how Khaenri'ah got its start?
So that would actually make the Sinner the Second Descender. The Second Descender is also likely the Second Who Came and we know that when it arrived it and Phanes came into conflict. At the end of the conflict it's implied that Phanes won so just like we saw in Caribert the Sinner was bound in chains and sealed inside of a purple crystal. Not only that but this crystal was housed in a large chamber that was guarded by an Abyss Herald but ++notably not from the Abyss Order.++
The timeline of events would go Phanes being summoned to tame the then purely elemental Teyvat which was chaotic as described by those same Tiara Artifacts. Then once ++Phanes++ tamed the dragons we get to the unified human civilization. Over time a population of them become disillusioned to Phanes and then accidentally summon the Second Who Came resulting in a major conflict that ended in the Heavenly Principles and fake sky.
So in this case that would push Nicole into being the Third Descender still with the task of finding the Genesis Pearl and therefore our MC is the Fourth but as a twin they share the position with their sibling who actually answered the summon while we only accompanied them.
Summary:
- Again the theory I'm still going with is that Phanes is the First Descender, Nicole the Sustainer is the Second who ended up in a major conflict against Phanes resulting in the Heavenly Principles and fake sky, our sibling is the Third who was meant to pick up where Nicole left off and then finally our MC became the Fourth after our sibling failed too.
- But Caribert's implication that Khaenri'ahns (or just anti-god humans in general) became followers of the Abyss and summoned it might be suggesting that the Abyss (the Sinner specifically) is the Second Descender.
- So in that case First is still Phanes, the Sinner is the Second who ended up in a major conflict resulting in the principles and fake sky, Nicole arrived as the Third to free the humans from said fake sky but was defeated by Phanes and brainwashed and then the twins both arrived as the Fourth but since our sibling joined the Abyss Order only our MC is counted as the Fourth Descender.
Which of these lists do you think is correct? Do you have another idea on who these guys will turn out to be?
Topic originally created on June 4th, 2023.