Wait, so why did the Archbishop... (SPOILERS)

[Anonymoose]

In regards to them supporting Thordan's Quest for Peace, his idea of "peace" was probably "slaughter anyone who opposes me," exactly as he tried to do to us. Definitely plays into the Ascians' plans.

Perhaps the Ascians were willing to roll the dice on him [A] not turning on them and [B] causing enough chaos to bring about Zodiark's return before resistance ended. Or maybe I'm just wrong in assuming that resistance would end. If someone displays an infinite wellspring of power, don't you just lay down your arms for the time being? Imagine the shock and awe of a defeat at the hands of a Triad-empowered Thordan and the Knights of the Round (assuming he also killed the Warrior of Light). I would expect things to just collapse into the Ishgardian Empire sooner rather than later, lol.

Then again, perhaps the eventual Isghardian Empire - Garlean Empire war would guarantee enough chaos to raise Zodiark.

[Cilia]

Perhaps the Ascians were willing to roll the dice on him [A] not turning on them and [B] causing enough chaos to bring about Zodiark's return before resistance ended. Or maybe I'm just wrong in assuming that resistance would end.

To [A], Lahabrea makes it pretty clear he never expected Thordan to betray him. He seems shocked and incredulous that he's doing so.

To [B], there's no way to know exactly. Going into the realm of theory, if the Warrior of Light died fighting the Knights of the Round and Thordan went on a "conquest of peace," doubtless the beast tribes would all summon their primals in response. If anyone fought back, there would be deaths. If it escalates to a war with Garlemald, that's an even higher death toll. All of that works in the Ascians' favor.