Revelations from Patch 5.5 (Part 1)

[Lauront]

It's possible that...

The very plan to revive the sacrificed ancients was conceived after seeing Elidibus return from Zodiark. While his exact nature is a little nebulous (save for the fact that he bears the traits of a Primal, like his power varying based on faith in him, and imprints of Zodiark's imperative), it is clear that his own soul was still there deep down (and remains in the Crystal Tower.) Hearing the disagreement that raged on is what prompted Elidibus to emerge, but it's not specified what exactly the disagreement concerned at that point, beyond stating the Convocation had lost some of its cohesion. Bearing in mind that this is a civilisation that had deeply seated notions of duty and of sacrifice for the achievement of a greater good, Elidibus's emergence may have served as a proof of concept of it being possible to revive the sacrificed ancients. Venat's faction, in all honesty, did not seem particularly caustic about the sacrifices per se, and acknowledged that the Convocation merely did what it though was best for the star's future (indicating it was at least parsable in their moral framework - it's vague what the "new life" was, anyway, but again the concept of duty/obligation to those who enabled the star to even continue existing could be the overriding factor, coupled with it being a quicker way to get things back on track.)

Their main rationale was to provide a check on Zodiark's power, to avoid their doom. So it looks to me like the issue was less so the sacrifice itself, and more the question of what it'd achieve - in this case, the return of the ancients and resumption of thing as they were, I suppose, coupled with fear of Zodiark's great power. Nonetheless, you're right that this plan originated with the Convocation - some may attribute it to tempering etc., and therefore to be at Zodiark's direction; while I may have been more amenable to such a possibility before, knowing what we do of Elidibus and that he was the Primal's heart, has left me less convinced of that. Especially as Elidibus gives you his account of what led him to emerge from Zodiark. It bears the hints, IMO, of a conflict exploited by someone who wanted Venat's faction and the Convocation to resort to violent conflict. Two well intentioned factions pushed into conflict, and then an out of control war between two primals, one of which at the least was without its 'driver'/heart. Even if Elidibus was able to regain control over him (as with Zenos assuming control of Shinryu), once they were locked in battle, that may have become impossible. I don't think Zodiark would exactly be impressed by the sundered state of the world that he was brought in to protect, but I agree that he may not be automatically hostile towards the MC, per se, and that the rage may stem instead from what was done to him... especially depending on how things progress with the Blessing itself, and the trailer's narrator...