Spoilers - plus help I don't understand the warriors of darkness storyline

[Aivi_lo]

snippety snip

Thank you so much for taking the time to explain the story in depth. I remembered bits and pieces of it, but I don't have the best memory and the story being broken up as it is doesn't help me!
I had to read your explanation 3 times, but think I understand it now. I had thought that the Warriors of darkness were just better than we were at stopping the bad guys and that's why their world was flooded with light. I wonder if hydaelyn is so weak because her light is effectively dammed away in the first world? And if she already had warriors of light /emissaries there, why she didn't act sooner (not that I'm not thankful minfilia is gone for a while!)
What are the different aspects of the crystals? Are there only six? I'm vaguely remembering collecting those in a previous instalment, but cannot for the life of me remember what happened with them in the end and why I still have one but the other scions don't.

[Griffey]

We gathered the crystals through the 2.0 storyline, giving us the ability to use the blade of light against Ultima and Lahabrea amongst other things. Hydaelyns power starts waning and we seem to lose them by the time we meet Midgardsormr, then we spend the rest of the 3.0 storyline getting them back.

[TinyRedLeaf]

I had thought that the Warriors of darkness were just better than we were at stopping the bad guys and that's why their world was flooded with light.

Yup, that's correct. Although, it may have been the case that the forces of Darkness were relatively weaker in the First, and that was why the WoD were so successful there.

I wonder if hydaelyn is so weak because her light is effectively dammed away in the first world?

My impression throughout the 2.x series is that Hydaelyn had spent too much of her Light empowering her champions in the Source, and that was why she was weakening, to the point where she could no longer directly communicate with her Chosen.

The Light/Dark encapsulated in the 13 shards were separated from the Source at the time of the sundering. While they are, in a sense, in a different place, I'm not sure if it's accurate to say they're being "dammed" away, because it's not like that was part of a deliberate plan. As Anonymoose described, it was an unavoidable consequence of Hydaelyn expelling Zodiark from the Source.

And if she already had warriors of light /emissaries there, why she didn't act sooner

It appears that Hydaelyn never created "emissaries" of the same nature as the Ascians — until now. She chose instead to directly empower "Warriors of Light", who, unlike Ascians, remain mortal and alive. Ascians, are, on the other hand, some kind of aetherial beings. They're immortal, but aren't alive the way the Warriors of Light are.

Having chosen to directly invest her power in the WoL, I assume Hydaelyn eventually passed the point of no return, where She no longer had the strength to create an emissary even if She wanted to. That was why She couldn't help the First, even though She heard the world's prayers.

What are the different aspects of the crystals? Are there only six? I'm vaguely remembering collecting those in a previous instalment, but cannot for the life of me remember what happened with them in the end and why I still have one but the other scions don't.

Each of the crystals of light represent one of the six elements of fire, water, wind, lightning, ice and earth.

Hydaelyn told the WoL at the very beginning of 2.0 to go forth and seek the crystals. And by the WoL's deeds, the crystals would reveal themselves to him.

The WoL is the only one among all those gifted with the Echo to have successfully collected all six crystals, which makes him by far the strongest champion that Hydaelyn ever empowered.

For some reason, Midgardsormr chose to strip the WoL of the blessings of light in 2.55, as a way perhaps to test his worth. And the WoL spent the rest of 3.0 re-igniting the crystals, and regaining their full blessing.

That's what makes him by far the most fearsome opponent that mortals and primals alike will ever face. In Elidibus' own words, the WoL's power is approaching that of the gods, and he feared the WoL is danger of upsetting the balance too much towards Light. That was why Elidibus decided to deploy the WoD to counter the WoL, at the end of 3.0.