Light and dark confusion

I've been playing this game for 3 1/2yrs now and the light/dark thing has finally dumbed me down.

our WoL is a grand hero who keeps saving everyone and solving problems, slaying anything thats scary but may end up bringing an apocalypse, and now i'm trying to understand why.

why are the ascians so hellbent on destuction
why are the garleans so hellbent on destruction.

and now after being on this forum and reading about different worlds/stars I think its time someone broke it down for me how after so much fighting to save we're heading towards oblivion instead.

A great sundering long ago separated Zodiark from Hydaelyn, and in the process thirteen dimensional shards ("Reflections of the Source") were created. The game takes place on the Source ("this very star"), where Zodiark is implied to be imprisoned in the white moon. Each time a Calamity happens, the barriers between the worlds breaks down and a Rejoining melds a shard back to the Source, deleting that world and slowly restores Zodiark (this has happened seven times so far). But apparently there's also the Balance between Light and Darkness as a factor: if a world gets too much shifted to either end, it becomes a void. The Thirteenth World (fathest shard from the Source) experienced a Flood of Darkness and is origin of the many Voidsent we encounter. The First World (closest shard to the Source) is on the verge of a Flood of Light "erasing all form and life."

Now on the Source, we have been told that twin dooms are coming: either the Eight and final Rejoining will occur, or the Source will (somehow) experience a Flood of Light like the First World. The ascian Elidibus is especially concerned with the balance of Light and Dark, which why he took the body of Zenos yae Galvus and intends to destroy the Warrior of Light. This is apparently also the reason we "must" become the Warrior of Darkness in Shadowbringers. What makes everything so confusing is the balance seems to work independently of Hydaelyn & Zodiark and hasn't been explained clearly.

The ambiguity of what balance really entails has probably been for the sake of the plot. By not giving it a strict definition until the 11th hour, they've kept their options open for what the plot will be when it finally gets to that point. But let's use some basic logic and hope for the best.

Theoretically, it can't be the case that Light and Dark must needs be in true æquus lībra (equal balance). We've been explicitly told that each shard possesses a different inherent balance of Light and Dark to begin with, and they've all gotten along just fine until the Ascians rocked the boat. Rather, it seems that each shard falls into its own unique homeostasis; dynamically returning to the same stable point in spite of its inequalities...until said boat is rocked. Even if this is true, Elidibus would leave it out of his speeches because it's inconvenient for his position.

I suspect that it is a sudden and dramatic shift in the balance which leads to a Flood; homeostatic processes would be prevented from having the time required to compensate. The boat rocks too far too fast, water spills in, and it sinks - the dimension is overrun by the imbalanced energy and the aether there is destroyed, leaving a dimension-sized nothing where the shard once was.

Light and Dark thus just seem to be the result of cosmogenesis, the primordial ocean of chaotic oblivion sorted into the basic units of existence. "The Star." The problem is that there is a will of Light (Hydaelyn) and a will of Darkness (Zodiark), and these entities seem to (incidentally) be governed by the nature you'd expect of their aspect. Not necessarily good or evil, but genesis and entropy, growth and decay, order and chaos, division and unification, creation and destruction, distinction and consolidation, benevolence and greed. Moreover, the wills cannot control their energies directly - at least within the corporeal world of "The Star" - and thus their agents are required to do so for them. And Hydaelyn isn't terribly good at this. (Or, if you subscribe to such beliefs, perhaps She's just not telling us the whole truth.)

The Ascians are so literally hells-bent on destruction because, as Zohar said, that's how Rejoinings occur and thus how Zodiark, their "one true god", is reborn.

The Ascians are hellbent on destruction because it's the easiest path for them to upset the balance of light and dark enough to rebirth Zodiark as mentioned above.

The Garleans however, are not actually hellbent on destruction. Most of their actual motivation is one of wanting power. Power to destroy the Primals, because they saw what they can do to the world (As mentioned when you end up going to The Burn in the MSQ). With this power, they look to take over the world as a secondary motive, because the further their influence spreads, the more power they gather because of sinister motives such as using civilians as test subjects (For things like the procedures used on Fordola)

Most of what appears to be the Garleans being hungry for destruction, is actually just the Ascians using them to push their own agenda. Be it in the form of promising power to high ranking Garleans (Which again, is what they seek, they want to be able to destroy primals to stop the world from having its aether drained and thus becoming a desolate husk a la The Burn), or by actively masquerading as Garleans, such as taking the body of Zenos.

One of the confusing aspects would be the fact that the Garleans are making deals with the Ascians, while the Ascians are literally aiding beast tribes with summoning the very Primals that the Garleans wish to see destroyed. However, it seems to come down to a similar thing to with the Archbishop in HW where the plan is to go along with them until getting the power to not only deal with the threats they made the alliance for (For the Archbishop, it was to deal with Nidhogg and his horde, for the Garleans it's the Primals) but also then destroy the Ascians themselves.

So, interestingly enough, on reflection, the Garleans and the Warrior of Light and the Scions actually have similar goals in mind. Prevent the Primals from sucking the world dry of aether and to destroy the Ascians. Which is why Alphinaud thought that there was in fact the possibility for a peace treaty with the Garleans. The main division between the Scions and the Garleans, is that the Garleans are prepared to make deals with the Ascians in order to gain the power to deal with the Primals, while the Scions rely on the Echo provided by Hydaelyn. (Well, that and the Garleans totalitarianism regime is not particularly welcome, their discrimination and lack of ethics when it comes to slavery, murder and torture of non-Garlean populations are less than desirable...)

thanks for all of the explanations, for me though it's tough to wait to see what triggers us to go dark, because doesnt that mean something thats technically really good is bound to happen in the lead up to or in the beginning of 5.0?

also, will we really be a soldier for darkness or more of a free agent thats finally unshackled from both sides, its called shadowbringer, not darkbringer.

Just seems from what i've played through and taken in from other players that with the scions being out, the alliance actually doing ok and garleans still being shifty as all heck that this would be the perfect time to actually unleash the WoL and let them truly fight free.

I labor to believe they'd do anything that'd make the story arcs of 2010+ a mistake and suddenly we're turning on Hydaelyn. (But you never know!) I think we had to do what we've done to get here, and we'll have to do this to get through it. If She loves us as much as She claims, She'll get over it. She can't control Light directly and no one wins if there's a Flood.