Regarding the 'soul' of an Eikon/Primal

[Cleretic]

Before Endwalker I would've said that this is indeterminate largely because of the nature of primal summoning, and I used to have a hypothetical about Ifrit, but I actually realized that the caster role quest literally is my old hypothetical with a few elements changed. (Spoilers for that questline, but it's ultimately not important):

Does Vaindreau, the malformed primal born of the Church's attempt to revive the Heaven's Ward, have their memories because he has their souls? Or does he have those memories because the guy that summoned him assumed that they'd have those memories, and so the product of his summoning had them? It's ultimately impossible to tell.

That said, Endwalker did indirectly answer this elsewhere: because primal summoning is bastardized creation magic, then primals are ultimately arcane entities. This means, like all arcane entities that are directly the result of creation magic, primals don't have souls--however, this wouldn't lead to a meaningful difference, as the existence (or lack thereof of) a soul doesn't change anything meaningful. There are exceptions, though--as KageTokage mentioned Shiva and Tsukuyomi would've had them, as would Thordan and the Knights Twelve, and Alexander (which actually has basically the same route to that result as Phoinix). Tiamat's testimony that she could tell the primal Bahamut wasn't her brother suggests he's not in that category.

Anima is a genuinely interesting gray area in that respect, though. Did Varis' body being used like that yank his soul back into play, similar to when we pulled in Emet's soul for the Seat of Sacrifice? Does a soul immediately leave a body on death in this universe, or is it there for a while, and therefore it got pulled in? Or was his soul not involved at all, and it was just a zombie situation? Personally I'd guess he's in there, largely because it would bolster Anima's whole concept; as the thing exists as the deified spirit of the Empire, it would make sense that Varis' spirit itself is shackled in there, but we ultimately just don't have any evidence for it.

[UkcsAlias]

Does a soul immediately leave a body on death in this universe, or is it there for a while, and therefore it got pulled in?

Maybe a soulstone can make a soul reside longer, and maybe also easier to restore? There isnt much lore about how these work. They seem to be able to keep the soul intact over time.

And since soulstones can interact with the owner of one (in both gaining and giving knowledge), there is quite a lot of options open here