Midgardsormr and the Crystals

[lololink]

The Knowns

It could end up being the case that the Twelve or Hydaelyn were involved

As for what Louisoix gives Alfie and Ali, I'm not sure. He talks about "an ancient art" that lets you summon a primal's power from its defeated essence. I thought he was literally bestowing on them permission to summon the closest thing he could offer to assistance: Phoenix-Egi (because they're Arcanists).

Still spoilers T12 :

The twelves are involved, you see them clearly surrouding Louisoix in the T12 cinematic :
( On the left the T12 scene, on the right the same blades being summoned as the twelve surrouding Bahamut )

Sure the twins might also be able to summon egis but the main thing here is that the primal chose to give their aether, in the case of Louisoix there wasn't much left after he was defeated, but the twelves still had a huge amount of aether, the aether that made Louisoix a primal didn't come from nowhere and you don't see him use his staff to gather the aether and use it on him, he was just waiting his death and then the twelve appeared to him, without any text and just watching the T12 cinematic it's obvious to me that the twelve gave their aether to him. The people were praying the twelves, not Louisoix directly.

[treuhavik]

Still

The Twelve were never fully summoned, though, making it extremely unlikely that they had a direct hand in this transformation. If they had been, Louisoux was pretty confident that they would have the same aether-hungry form as our known primals. The vision of the Twevle was only that--a depiction of the ritual. Once the last attempt to command their summoned power failed, the aether being used for this was turned inward, toward Louisoux who then became Phoenix with said aether and the prayers of thousands seeking a savior.

It's all pretty cut and dry, IMO. This cinematic was revealed to solve the mystery, not pose more questions or serve as fanon fodder.

/10characters

[Anonymoose]

The twelves are involved, you see them clearly surrouding Louisoix in the T12 cinematic

Might as well continue the spoiler tag tradition:

That's what I mean; are you sure that those spires are The Twelve? You're certain that, canonically, they're guaranteed to not be half-summoned crystalline eikons brought about by Louisoix's ritual, and guaranteed not to be manifestations of the Twelves' attributed powers given form by the prayers of Eorzeans, but The Twelve? So far, I lack that certainty, and so I am hesitant.

the aether that made Louisoix a primal didn't come from nowhere and you don't see him use his staff to gather the aether and use it on him, he was just waiting his death and then the twelve appeared to him

In Louisoix's own telling of the events he accounts for the aether's source and how it was bestowed upon him.

Little choice remained to me. I used the last of my strength to entrust our hope unto the future, and prepared to meet my end. As you have no doubt surmised, I did not perish. When the cage built from the essences of the Twelve was destroyed, the sky was filled with a colossal cloud of aether... This drifting energy responded to the prayers of those fighting below─and to my own desperate wish that the dying realm be saved─by infusing me with the power of a primal. I became the immortal Phoenix, ancient symbol of rebirth.

Of course, that this doesn't rule out the spires being the Twelve in any way; I'm not trying to say that at all. I just don't find it to be self-evident, either. I'm still in that gray area of "That could have been the true Twelve, but it could just as easily have been man-made artifacts of a half-completed summoning ritual." That's the line of confusion SE want's us to tread, isn't it? They even used that word, again - "essences."

If it was confirmed that The Twelve just step in and make primals, that'd throw open a lot of doors and slam shut a lot more. We'd need to start a lot of our discussions over again from scratch.