The echo and Hydaelyn's contact

[Rosenstrauch]

Granted, it's still not clear how the Echo prevents tempering, or if it does so at all in light of Emet-Selch's admission that all the Ascians were tempered by Zodiark when they summoned him. My best guess is still that we are tempered by Hydaelyn, but owing to her raison d'etre she doesn't compel service or influence our behavior in any way.

One thing that muddies the water even further is that both Fordola and Zenos possess the Echo through artificial means. Fordola uses it to stop Lakshmi's attempts to temper the NPCs alongside Arenvald and WoL during a solo duty, and Zenos uses it to not only resist Shinryu's attempt to temper him, but is able to subvert the primal's will and take control of it himself. Unless both of them are tempered by Hydaelyn, too, it does seem like the Echo provides resistance to tempering on its own. It might just be that it relies on the strength of the person's will—the Convocation weren't strong enough to resist Zodiark, whereas Fordola and Zenos were strong enough to resist Lakshmi and Shinryu respectively.