The Reasoning behind The Sundering? (*6.0 Endwalker Spoilers*)

[Vyrerus]

A bit (read: very) late on getting around to this, but I just so happened to get the Hades fight in trial roulette yesterday and remembered this portion of the debate. I looked at the buff you get during the last phase, and the text for it says outright that you are using the "light trapped within." The ring you fight in, as well as your ability to break free from Emet-Selch's spell in the first place, are quite clearly intended to be the result of the light you absorbed being put to use. This is something enabled very likely through a combination of Venat's ward and Ardbert's sacrifice, but it is not a direct act on her part.

The key to this portion of the Hades fight is found in Hades' dialogue after he inflicts, "Life in Captivity" on the party. You're wrapped in chains, and get the ATE which is labeled, "Unleash Light." The ATE is preceded by the text, "The Light within Her champions grows faint..."

When you break the chains at the end of the ATE, Hades ponders, "Has the Wardens' light won free? No... DAMN YOU! DAMN YOUR WRETCHED BLESSING!"

The combined light being expelled from the party turns the stage white, and you go from having the buff, "Light Beyond Darkness" to having a buff from the floor called, "Light in the Dark."

You go on fighting Hades, and he says, "I will extinguish the spark of your miserable lives!" And then casts Dark Devours multiple times. He has a voice line after each chain of Dark Devours causes the Light within the arena to grow smaller.

"That Light split the world and every life upon it!"

Dark Devours

"Our tragedy must never again come to pass!"

Dark Devours

"By His grace will Darkness reign over all!"

The Darkness becomes an impenetrable shroud, encompassing all.

"Death comes for Her servants."

Enrage cast of Black Cauldron begins.

While you might not be wrong that it's not a direct intervention, the Blessing is so apparent in this moment that Hades sees it as what's contesting him rather than us or the Lightwardens. I don't doubt that the Lightwarden juice is the fuel for it, but it's the Blessing doing Goddess's work.

[Jandor]

The Blessing is a car, the WoL is the driver, and the Lightwardens are the petrol.

You're not going to get anywhere fast without all 3.

[Absimiliard]

While you might not be wrong that it's not a direct intervention, the Blessing is so apparent in this moment that Hades sees it as what's contesting him rather than us or the Lightwardens. I don't doubt that the Lightwarden juice is the fuel for it, but it's the Blessing doing Goddess's work.

That would be precisely the point I am making, yes. I'm not denying that Venat's ward was a key component. It was, elsewise it's doubtful the WoL could have contained all that light, let alone actively used it without becoming a Lightwarden. The ward prevented their aether from being corrupted by the light (which I'll note is its primary function according to Endwalker), the WoL's strong soul and absurd force of will enabled them to contain that light as long as they did, and Ardbert's sacrifice strengthening them further was more or less the missing piece that allowed their near-to-shattering soul to stabilize long enough for them to channel it.

What I've always figured actually happened (and I do grant that this is mere supposition on my part) is the excess light being used to empower the ward, thereby allowing it to momentarily reach the potency we saw from it back in ARR when it formed a barrier to saveus from Ultima (though, in the case of Ultima, that was clearly direct interventionon Venat's part) and thereby expand outward to contest Hades' darkness directly.