Garleans and the ancients. (Spoilers)

[Kesey]

To add to my previous post; other past Azem lives:

Ramza (the ff14 version, from the past, who actually fought Ultima) from the Return to Ivalice raid.

During the Warring Triad, the machinery in Azys Lla recognize us as a citizen of the Allagan empire during the war with Mercaydia.

Finally, we were at the battle of Carteneau before Louisiox sent us away (to the beginning of the ARR). The cutscene from Coils even paint us as looking like Ardbert there (which is a nice nod from the devs).

[Rosenstrauch]

To add to my previous post; other past Azem lives:

Ramza (the ff14 version, from the past, who actually fought Ultima) from the Return to Ivalice raid.

This one is not necessarily true, as Past!Ramza possessed his present day counterpart at certain moments in the Return to Ivalice plotline, and also came to our aid alongside Mustadio, Agrias, and TG Cid. Unless time travel is involved, that would mean his soul was still lingering in the world up to that point and thus couldn't have reincarnated.

[Kesey]

This one is not necessarily true, as Past!Ramza possessed his present day counterpart at certain moments in the Return to Ivalice plotline, and also came to our aid alongside Mustadio, Agrias, and TG Cid. Unless time travel is involved, that would mean his soul was still lingering in the world up to that point and thus couldn't have reincarnated.

Maybe I'm wrong about Ramza. But he was a person traveling the world, fixing problems and gaining friends during a major war. He has all the hallmarks and wore the mantle of Warrior of Light in the ff14 version.

Plus, I believe we only need a fraction of our aether for the reincarnation process, but this is based on what Ascians say about the process. So it stands to reason like other ghosts in the game its when some aether is left behind by the departed, but rest is reincarnated. No need for time travel.