Primals - A Discussion on Ethics & Philosophy (ARR & HW Spoilers)

[Anonymoose]

Where was it shown of Ysayle being about to revert back from the summoning on her own?

In each summoning (Akh Afah / Thok ast Thok / Gration), we see Ysayle exhaust herself; Shiva is basically beaten out of her. This suggests that (assuming she didn't actively consume crystals and draw from the land as would a normal primal) she could simply wait for the tank to run dry (or actively expend the energy) to cause the primal essence to withdraw at any time. See Phoenix; Louisoix was the primal and even he was able to relinquish his hold on the aetherial power at will.

Thordan might also serve as an example if everything about him wasn't a seeming contradiction. Nabriales says that the Echo is required to host a primal; Thordan doesn't have it (as far as anyone knows). His mortal frame being so stuffed with power ostensibly contributed to Louisoix's death; it didn't bother (the allegedly Echo-less) Thordan at all. The Knights of the Round could shape-shift on a whim. Yoshida-san says that only Thordan was a primal and the Knights of the Round manifested through his power (implying that he'd already been infused with Thordan along the way at least to a degree); the lore book says that Thordan's summoning ritual was perfected through practice on creating the Knights of the Round's primal forms first. And both interpretations explain Zephirin.

As someone trying to keep the archives in order, Thordan is a constant source of frustration.