I would argue that they do temper mortals, just in a more limited way: the Padjai. They are Hyur children who are chosen by the Elementals, which causes them to be born with horns (for...some reason) and have a natural affinity towards nature and conjury. All Padjai we have seen in the game are dedicated to the Elemental's cause and unable to defy them. I'd say that's tempering right there.
If I had to speculate, I'd say the Elementals are some kind of aetheric pressence limited to the Black Shroud. That would explain why they have been weakened by the Calamity: their aetheric sustenance comes from the forest itself, instead of piles and piles of crystals like the Primals.
If I had to speculate, I'd say the Elementals are some kind of aetheric pressence limited to the Black Shroud. That would explain why they have been weakened by the Calamity: their aetheric sustenance comes from the forest itself, instead of piles and piles of crystals like the Primals.