Is it really the end? *Spoilers*

[Iscah]

I dont think shiva ever actually tempered anyone. She actually used the same kind of transformation the Ascians used, like elidibus being the OG warrior of light or Hermes with with dungeon boss form. Yasyle secretly mastered this power before the devs wrote / revealed this plot power to us. The only difference is she needed to get the power externally which limited her , as opposed to the asians who have tons of aether and creation magics.

The script in post-ARR (and possibly still into Heavensward) definitely pointed towards her "heretics" behaving in a similar way to the tempered thralls of the other primals, which IIRC was what tipped us off to it being something particularly concerning in the first place.