Rejoining question SPOILERS

[Iscah]

It might also help to remember that the story Mitron and Loghrif told the Shadowkeeper directly contradicts the story Elidibus told Ardbert in some ways.

I assume Elidibus's story is "version 2" when the situation changed from carefully setting up both worlds for a Rejoining to "the First just hit flood state and the Source isn't ready, but maybe I can salvage this if I move quickly enough and get these guys to do the dirty work".

[Zackneifein]

Our earlier theories (pre-Shadowbringers) were based on Ardbert's understanding that killing the Ascians directly caused the Flood - and because of that we assumed that Ascians must be 'cosmically aligned' to Darkness and keeping the balance. That information is outdated now.

I haven't actually got to the final role quest yet so I'm going on why I've heard from others, but my understanding is that killing Ascians (who we now know to be "just people", if extremely powerful ones) isn't inherently a problem - but killing the person carefully manipulating the balance of Light and Dark without being aware of what they were doing, and especially just after you've altered the balance in a direction they didn't anticipate, is going to cause that plan to fail and the careful balance to tip, and suddenly the world is in a Flood state it was never supposed to actually reach.

I still think that Ascian are "cosmically" aligned to the Darkness.

What we now know, is that Light and Darkness are more complicated than "Good and Evil".

But even if we are called Warrior of Darkness in the First, we still have the Benediciton of Light, we are Light aligned due to our connection to Hydaelyn who is aligned with Light (we also know that contrary to previous assumption, she isn't the Origin of the Light nor she have an absolute control over it).

Same for the Ascian, even more the Three unsundered Ascian that are tempered by Zordiark. They use Darkness power, call over the Darkness for their powers as much as over Zordiark.

Even at the end the fight with Hades, we are the "Light in the Dark" and the description of the buff clearly state that we are defying the Darkness by fighting Hades.

[Erendis]

The First was already Light-heavy, but had fallen into a delicate homeostasis. The Shadowkeeper was supposed to help break that homeostasis and tilt a bit farther towards Light (the path of least resistance, I suppose), which would pull all of the elements to an unnaturally umbral charge and cause it to begin to diffuse into the Source. Striking down the Warriors of Light while triggering a disaster on the Source would have led to a Rejoining. Instead, the Warriors of Light defeated and spared the Shadowkeeper and killed her masters, causing a violent lurch even farther towards the Light.

I do not know if First's Ascians were native to the First, but following this logic, would not the First be tipped even more to light after we killed Emet-Selch?

[Zackneifein]

We killed Emet-Selch by using the corrupted Light aether of the Lightwardens against him.

And it was a lot of it, so it's probable that our act against the Sin Eater and the disappearand of the Lightwardens Light aether restored the balance between Light and Dark enough to prevent a Rejoining, Emet-Selch death or not. But the First is, even now, in a preocupying state, just not as much as before.

It's Ryne and Eden that will restore the balance between Light and Dark, and all other elements with a more durable effect.

[Rannie]

Ryne Eden and our drugged up versions of the primals that we're summoning and killing =p