Major Spoilers for all Expansions - Some general things I didn't understand

[Arlythe]

Hello everyone,
There are a few things that I didn't quite understand during the story from A Realm Reborn to Endwalker, and I hope you can help me.

1. As far as I understood it, Dynamis is essentially the counterpart to Aether. Dynamis creates life and gives it form, and Aether fills that life with all its aspects, darkness, light, earth, fire and so on. Why do Primals need Aether crystals to be summoned, whereas the inhabitants of Ultima Thule are entirely composed of Dynamis?

2. Aren't the Twelve essentially Primals with extra steps?

3. When we use the Azem crystal to summon people from other dimensions, where do they come from? From the Shard Worlds or from alternative versions of the Source? Do we form them with Dynamis? How do we know it works, does it work like a job crystal?

4. Why can the Omicrons easily resurrect beings that have died? Doesn't that make death inconsequential to the storyline in FFXIV? For example: In the Aetherstream where we fought against Amon, we saw Haurchefant's soul. Why can't we encase it in a crystal, bring it to Ultima Thule, and resurrect Haurchefant there?

5. When we speak to Metrion in Ultima Thule, Hythlodaeus and Emet-Selch appear and summon a bed of Elpis flowers. Why can they do this? Why do they have consciousness, and even more importantly, why do they still have the power to create things? Shouldn't they just be projections? And why do they remember Metrions doings? Didn't it get wiped?

[Cilia]

Here we go.

1. Dynamis and Aether are just different forms of matter, analogous to real-world dark matter and... regular matter. The universe is composed of both (though it's actually, iirc, 2/3 Dynamis), though Aether overpowers Dynamis unless the latter is extremely concentrated. Primals are basically just aether engines; crystals are just highly concentrated forms of aether, which is why primals like them so much. The inhabitants of Ultima Thule are Dynamis-based recreations, but have some amount of Aether once the story gets rolling.

2. Yes, although there's a couple of wrinkles: they aren't primals like the typical kind we fight, instead being closer to "true" creation magic lacking the drawbacks of the primals summoned via the Ascians' rites taught to people in contemporary times; and they use the souls of Venat's collaborators as a base.

3. Not clear. Wherever they were beforehand; unless it's a named NPC you can think whatever you want.

4. I'm going to need a little more clarification, because I don't remember the Omicrons resurrecting anyone.

5. Hythlodaeus and Emet-Selch are able to do what they do in Ultima Thule because... they're Ancients. Having not fully dissolved into the Lifestream yet on account of their (relatively) recent deaths, we yanked their souls out for one last favor. At that point they remember things as they were because death undoes the memory locks set in place by Kairos.

[Arlythe]

4. I'm going to need a little more clarification, because I don't remember the Omicrons resurrecting anyone.

Of course.
It happens in Ultima Thule during the Omicrons' tribe quest. You restore the café we find in the MSQ right before Alphinaud and Alisaie lose their bodies to form the stairway.
In order to reopen the café, you need customers, so you start resurrecting the Soldiers, the Grebuloff and the guys whose name slips me right now (They summon that Sphinx like Boss, Ra-La, at the end) you can see their worlds of during the dungeon "The Dead Ends" and find out what they loved to eat the most.
One by one they start using Dynamis, recreating parts of their homeworld and even create more of their kind.

[Zero-ELEC]

Hello everyone,
There are a few things that I didn't quite understand during the story from A Realm Reborn to Endwalker, and I hope you can help me.

1. As far as I understood it, Dynamis is essentially the counterpart to Aether. Dynamis creates life and gives it form, and Aether fills that life with all its aspects, darkness, light, earth, fire and so on. Why do Primals need Aether crystals to be summoned, whereas the inhabitants of Ultima Thule are entirely composed of Dynamis?

2. Aren't the Twelve essentially Primals with extra steps?

3. When we use the Azem crystal to summon people from other dimensions, where do they come from? From the Shard Worlds or from alternative versions of the Source? Do we form them with Dynamis? How do we know it works, does it work like a job crystal?

4. Why can the Omicrons easily resurrect beings that have died? Doesn't that make death inconsequential to the storyline in FFXIV? For example: In the Aetherstream where we fought against Amon, we saw Haurchefant's soul. Why can't we encase it in a crystal, bring it to Ultima Thule, and resurrect Haurchefant there?

5. When we speak to Metrion in Ultima Thule, Hythlodaeus and Emet-Selch appear and summon a bed of Elpis flowers. Why can they do this? Why do they have consciousness, and even more importantly, why do they still have the power to create things? Shouldn't they just be projections? And why do they remember Metrions doings? Didn't it get wiped?

1. Dynamis does not create life. Dynamis is a form of matter just like aether, analogous to real world dark matter. Primals need aether because they're built off aether, as inefficient as they are intentionally. It is unclear what exactly what all the inhabitants of Ultima Thule are made of, but they have physical forms, and indeed, everything in Ultima Thule has physical forms, because of the hope that suffused the area, although it was initially because of Thancred's will. Ultima Thule works less on direct logic and more on "feel". Don't think too hard about it.

2. The Twelve are constructs created by Hydaelyn with their cores made of fragments of the souls of her collaborators. However with time, they've been changed and supercharged by the prayers of their adherents. They are primals in the way that any aether construct is a primal, i.e. being aspects of creation magics.

3. It is intentionally unclear where the people come from. It is up to your interpretation. Maybe it's summoning some of your Warrior of Light's Free Company friends, maybe it's summoning heroes from beyond the rift. You get to decide who and what you're summoning.

4. The Omicrons in Ultima Thule can create life in the same manner that Omega could create life during the Omega raid series. Their advanced technology can replicate beings using their "blueprints" as it were, like how Omega replicated Alpha based on the interdimensional records of the Chocobo protagonist from the Chocobo series. The few beings they create are either based on Meteion's recollections from the Dead Ends or Stigma-4's Dreamscape. However, besides some of the initial replication, around half of the Last Dregs' customer base are pre-existing dynamis based beings originally given shape by Thancred's will and then sustained by the hope that permeates the area. As for why we can't do that, the better question is, why would we want to?

5. Hythlodaeus and Hades are capable of creation magics as they are ancients. They were summoned "to life" from the lifestream by the supercharged Azem crystal, empowered by Hydaelyn to be able to bring back people, as shown soon after by being able to bring back the Scions. At no point does Azem crystal create projections. They remember Meteion's doings because memory alteration magics get wiped clean the moment you die, as explained by Scholarch Montichaigne.

[Cilia]

Of course.
It happens in Ultima Thule during the Omicrons' tribe quest. You restore the café we find in the MSQ right before Alphinaud and Alisaie lose their bodies to form the stairway.
In order to reopen the café, you need customers, so you start resurrecting the Soldiers, the Grebuloff and the guys whose name slips me right now (They summon that Sphinx like Boss, Ra-La, at the end) you can see their worlds of during the dungeon "The Dead Ends" and find out what they loved to eat the most.
One by one they start using Dynamis, recreating parts of their homeworld and even create more of their kind.

I haven't done the Omicron quests on account of abandoning crafting after 2.X...

... but the most likely answer, or at least the best I can come up with, is that while it's possible for the Omicrons to recreate things, we and the Loporrits involved have committed to an unspoken non-interference clause since importing all of the Omicrons' advanced tech into Etheirys would cause chaos. Besides which one of the central themes in Endwalker is embracing the ephemeral nature of life, so while resurrecting people with the Omicrons' tech is theoretically possible we aren't going to do so.

[Arlythe]

4. The Omicrons in Ultima Thule can create life in the same manner that Omega could create life during the Omega raid series. Their advanced technology can replicate beings using their "blueprints" as it were, like how Omega replicated Alpha based on the interdimensional records of the Chocobo protagonist from the Chocobo series. The few beings they create are either based on Meteion's recollections from the Dead Ends or Stigma-4's Dreamscape. However, besides some of the initial replication, around half of the Last Dregs' customer base are pre-existing dynamis based beings originally given shape by Thancred's will and then sustained by the hope that permeates the area. As for why we can't do that, the better question is, why would we want to?

Because I miss him. Jokes aside, so to simplify, Stigma or any other Omicron capable of resurrecting could form a new Haurchefant in my example, if they knew him or had substantial information about him, but he would be more of a copy, rather than the original person. Also, they mention that the species they resurrect are bound to Ultima Thule as it's their point of creation just as much as the beings like Kefka, that get summoned in Alpha, Delta and Sigmascape are bound to their dimension, if I got this right?!

5. Hythlodaeus and Hades are capable of creation magics as they are ancients. They were summoned "to life" from the lifestream by the supercharged Azem crystal, empowered by Hydaelyn to be able to bring back people, as shown soon after by being able to bring back the Scions. At no point does Azem crystal create projections. They remember Meteion's doings because memory alteration magics get wiped clean the moment you die, as explained by Scholarch Montichaigne.

Completely forgot about the supercharging and Montichaigne's words. Thanks for the reminder.

[Cleretic]

As the main thing unaddressed, I'll talk about #4:

The Omicrons are essentially bringing the records of people back as hard-light holograms. There's significant limitations to this--they can only do that to people that they have some sort of record of (which narrows it down to basically just 'Ultima Thule/Dead Ends denizens'; worth noting that they couldn't get the Nekropolis' people which gives you an idea of those limits), and there's likely some other limitations that we're not aware of because that doesn't really come up in the story. We know they can eat, and that they have enough sense of self and emotional presence to manipulate dynamis, and that's... well, kind of it.

They also don't simulate a lot of people. The reason why there is inconclusive, but I can think of at least two good reasons: either they only have finite capacity for creating those people, or--I think the more narratively compelling reason--they correctly recognize that all of the Dead Ends' civilizations would cause major problems if brought back en masse: The Grebuloffs are probably the safest but still have an incurable disease, the Karellians were at war and are still mad enough about it that it took being talked down for even just two of them to not kill each other, and the Nibirun are only relatively safe because they didn't have enough numbers amongst themselves to reach and enforce their 'everything should die' consensus.

But ultimately, everyone they bring back are simulations, not the original. They're real enough to be a person for all relevant intents and purposes in the Last Dregs, and they can learn to move on and live their own life free of the problems that brought the original to their end, but nothing suggests that we're actually looking at the real person. If you brought some sort of crystal containing all of Haurchefant's information (already a big ask, I don't know how you'd do it), and then convinced the Omicrons to simulate him (probably less of an ask, but still one), it wouldn't be Haurchefant: it would be a very convincing simulacrum, but it wouldn't be the real person. The dead guy is still dead, you just made a doll of him.

EDIT: Actually, now that you mention it, yeah the Last Dregs were absolutely populated by the same method that was used for the Omega raids. They're a little bit more real because at least the people in the Last Dregs certifiably existed at some point, but they're still just simulations, albeit pretty robust ones.

[Denishia]

Add onto this with the Ea creating the Miw Miis explicitly with dynamis and the implication that they might not be (just) simulacrums like the rest of Ultima Thule (Either via Thancred and Endsinger or the Omicron) but have souls from the now released Bird's Egg

[Frizze]

I haven't done the Omicron quests on account of abandoning crafting after 2.X...

Um... good news? This one is actually a GATHERING tribe. Activities for miner, botanist, or fisher. No crafting required. Thats the lopporits.

[Enkidoh]

On the point of the Azem crystal, it was stated when you first received it that it has the power to "draw your closest comrades to your side", so therefore it's not that much of a stretch that other players that are 'summoned' by it in duties are meant to be your closest friends, in other words, they're fellow adventurers from the Source.

Although there is a bit of willing suspension of disbelief needed to ignore why you have no interaction with them - consider it somewhat like a story-based Duty Finder in a way that automatically finds and pulls in adventurers to you for the battle (cue the horrified realization of just what that means - where someone might be in a difficult situation like in the bath or on the chamber pot when they're 'summoned' by the Azem crystal and arrive definetely not ready for battle! ).

Either way, it's just like in ShB with G'raha's summoning spell at the Dying Gasp, the power of Azem summons people you personally know and trust to your side instantly, wherever you are. So that question is therefore is really easy to answer as the game already pretty much states it: the fighters summoned by the Azem crystal are just other adventurers from the Source that you've journeyed with.