The Lost City of Amdaphor and the Sineaters

[Anonymoose]

Might want to pop back and check the explanation Urianger gave in Il Mheg in front of the MTG chart

I can grab the transcript, no worries there!

What Urianger stresses is that elemental aether can be pulled by proximity to Light or Darkness to give it a polarized charge. When an element has been charged, we say that element is astral or umbral. There is astral fire, there is umbral fire, there are elemental mixes that can become "astral energy" or "umbral energies". However, "astral" and "umbral" aether/energies are elemental, as in part of the elemental energy spectrum, and the charges of the elements solely arise due to proximity to Light/Darkness.

An element with an umbral charge is not identical to Light, the force which caused that charge.
The elements and Light/Darkness, strictly speaking, aren't even on the same energy spectrum.

That's why you can't have a "Calamity of Light", but a calamity of umbral elemental energies caused by Light.

It's the whole basis of his explanation: Eorzea named the charges and misattributed their causes. The First focused entirely on the causes and skipped considering "astral" and "umbral" as independent things in the first place.

Urianger

Dost thou recognize yonder chart?

Indeed. 'Tis a rendering of the elemental wheel, such as one might find in classrooms across the Source.

As the chart maketh plain, our world is composed of six elements, in addition to which there exist two poles in fundamental opposition.

Astral, the active; umbral, the passive.

As a reflection of the Source, the First naturally compriseth the selfsame forces, yet curiously, there is a notable divergence in their nomenclature. To be specific, the denizens of this world employ not the terms astral and umbral.

Thus was I moved to inquire what names said forces had been assigned. A simple question which yielded a most unexpected answer...

Upon demanding the name of the pole aligned with activity and growth, I was told that as life's myriad colors combine to produce black, the people of the First had called it “Darkness.” At this did my mind begin to race.

Yet 'twas only when I asked what name had been given to the pole aligned with passivity that mine eyes were opened to the truth. Peace and tranquility being as purest white unmarred by color, I was told, it had been given the name of “Light.”

Thancred

That's umbral light and astral darkness, yes? ...I'm no aetherologist, but it strikes me that the nomenclature of the First is rooted in the generation of the two forces, while our own appears to focus on their effects. Which makes one wonder...have we had it backwards all this time?

Urianger

'Tis indeed a compelling question, and one which beareth closer examination. Yet what knowledge we already possess sufficeth to explain the chain of events.

The phenomenon of aetheric thinning observed in the Source is the consequence of Light─the power of stasis─flowing in from the First to stifle the movement of aether within the land.

And according to Master Alphinaud, Black Rose slayeth by halting the circulation of aether within living beings.

Should such a weapon be unleashed even as the First were rejoined, replete as it is with Light...

Thancred

...We would have a disaster of untold proportions on our hands. A calamity.

Well...at least we have a better grasp of what we're facing. Our objective, however, remains unchanged.

You can see the deliberate separation of ideas when it's important to the plot.

Urianger
And therefore the true nature of the Flood of Light?

Ryne
Yes. It affected the balance of all of the aether in the Empty, shifting it so far towards the umbral that it stopped flowing altogether.

And perhaps more useful, it was confirmed by loremaster Banri Oda through Metatron Koji Fox

Gamer Escape:
Once upon a time, the only binary in the game was [astral & umbral]. These polarities existed in all things, and seemed to be part of the six elements rather than independent forces. Since A Realm Reborn, a second binary exists: [Light & Darkness]. As one might expect, NPCs don’t seem very well informed about these concepts, using phrases like “void energy” and “umbral energy” and “Dark energy”. As time went on, we even started to see Dark and Light sprites! Can you help us understand the boundaries for these concepts? Are they in any way related?

Koji Fox
So, you have the elements—and it’s still six elements, there are no newly-discovered ones. Those elements have charges—umbral and astral. If something has “umbral energy”, it is one or more of those elements, individual or combined. So if elements have an umbral charge, it can be said that they are “umbral energies”. That’s where those terms come from, “astral energies” and “umbral energies” are not individual things, it’s a blanket term. Light and Dark are not elements, but they are energies…in a different sense. They are not elements, they are not of the elements, and they are not astral or umbral. It’s a different type of energy. You might see a Light and Dark sprite and think, oh, they must be elemetals, but those are made of an entirely different form of energy.