#ask anne

Reincarnation is definitely canonically a thing, because the Warrior of Light is a reincarnation. Azem's soul was sundered into fourteen shards, but that was thousands of years ago. The Warrior of Light is a reincarnation of the Source's shard of Azem. Similarly, Fandaniel as we know was born as Amon, a reincarnation of a shard of Hermes. On this point, canon is pretty clear.

Such souls, when they are reborn, have no conscious memory of their former lives. To what extent they may be said to be the same person is questionable. While the Warrior of Light as written is suggested to have some characteristics in common with Azem--an affinity for travel and adventure--to what extent they are like Azem is left open to the player to interpret. In the case of Amon, he tells us that even when he was brought into the Ascians and received memories of his past life as Hermes, he was unable to relate to those memories or integrate them into his sense of self, and remains a very different person than the Hermes we meet in Elpis. Notably, when we meet this soul again in the Aitiascope, it takes the form of Amon, not Hermes.

But do all souls remain discrete in this way after death, reborn with the boundaries of the same soul intact if not the memories? Encyclopedia Eorzea seems to say no. Volume 3's section "The Aitiascope" (p. 225) is illuminating on several counts.

Reports of their foray indicate that their progress was impeded when the essences of their former enemies took shape to block their way. However, negative emotions are not all that linger in the aether, and the souls of erstwhile allies forged a path in that endless abyss to guide the Scions to their destination...

While it's not explicit, I think you could conclude from this that strength of emotion is at least one reason why souls might linger in the aetherial sea without dissipating.

Amon the Undying This fragmented soul deep in the aetherial sea once belonged to Hermes--ere it was sundered by Hydaelyn and reborn countless times over the ages. Yet the spirit that lingered in the Scions' path was neither Hermes nor the more recently active Fandaniel, but that of the Allagan technologist Amon through and through.

This confirms the cycle of reincarnation, and it is therefore reasonable to assume the Warrior of Light is far from the first reincarnation of the Source's Azem shard, likely having been reborn again and again over the ages. (Infinite OC possibilities...)

Rhitahtyn the Unshakable A fragment of the soul of Rhitahtyn sas Arvina, praefectus castrorum of the XIVth Legion. Though his essence had already partly merged with the aetherial sea, Rhitahtyn clung to existence, refusing to surrender his obsession with the adventurers who had thwarted Gaius's grand ambitions. His form was demonic in appearance, the desire to mete out vengeance twisting his spirit beyond recognition.

This is particularly interesting! The Rhitahtyn we meet in the aetherial sea is not an intact soul. His has begun to dissipate, and this accounts for the strange form the remnant of his soul takes.

Okay, here's where I'm going to get speculative!

If we were to take this a step further, I think we could question whether the souls of our allies--Haurchefant, Minfilia, Ysayle, etc.--that we meet in the aetherial sea are still whole. They do not manifest in their full physical forms, but only as disembodied symbols--Haurchefant's shield, Ysayle's ice crystals. Y'shtola with her aethersight recognizes Papalymo's aether, but describes it as "His will, given form," rather than as Papalymo himself. What takes form from each soul is the aspect of them the Warrior of Light needs to reach their goal. I don't think we could necessarily stop and have a conversation with them as though they were still alive, even if we wanted to.

My interpretation is that the dissipation of the soul into the aetherial sea to recombine with the aether of others is the normal state of things. It takes time, and how much time depends on the individual, the strength of their emotions and memories, the circumstances of their death, perhaps a sense of unfinished business, any number of other factors and perhaps also an element of randomness. But it is normal for this to happen. I think the souls that are reincarnated fully intact are probably the exception rather than the rule.

Furthermore, I would hypothesize that this is more likely to happen to souls directly descended from the original sundered, which I don't believe everyone is. This will probably be a point of contention for some, and that's fine; this is just my interpretation and I don't think I can prove it from canon, but I personally do not believe every person in the world is the direct reincarnation of a sundered ancient (which wouldn't really be logistically plausible unless the population of Etheirys has remained completely stable ever since the Final Days, which is doubtful). I likewise do not believe that every person has shards on the other reflections. I think most of the population are "new" souls--recombined from the aether to the extent that they could not be tied back to any specific ancient soul. Further, I think these "new" souls are not capable of awakening to the Echo, because they do not possess enough intact memory of the Final Days to respond to the trigger. If memory can be etched upon the soul (as Amon suggests to us in the Aitiascope, recalling strange dreams of the Final Days from before his memories were restored), then the dissipation of the soul would also destroy any residual memory.

So, in a nutshell, how I see it:

Reincarnation exists, but not all souls are reincarnated intact.

Most souls eventually dissipate into the aetherial sea, and their memories with them, to be recombined into entirely new souls.

Intact shards of the ancients who witnessed the Final Days are more likely to remain intact, and thus retain residual memory of the Final Days, allowing them to experience the Echo if the right circumstances trigger it.

Most people aren't direct shards of ancients; those who are recognizably a shard of an ancient are outliers.