Warning: Major spoilers following.
(Yes, I'm aware the anime is 'old news', but the spoiler warning doesn't hurt.)
It is established in the anime that the heros of the Taisha can 'bloom' to increase their strength, and that
this 'blooming' causes them to lose a bodily function (one eye's vision, taste, voice, one ear’s hearing) upon returning to the everyday world.
Similarly, from Tougou's and Yuuna's meeting with the former hero, it is established that this process seems irreversible because they are 'offerings to the divine tree'.
However, during the last episode,
despite having bloomed multiple times (and in Karin's case, having a part of her body 'chained' each time), the girls regain the bodily functions they have lost — and even those they lost in the former bloomings, i.e. in Tougou's case she can even move her legs again.
Is there any explanation given either in the anime itself (which I must have missed) or in derived works as to how what is put into the second spoiler box is even possible? It seems to contradict everything we learnt about the hero system in the preceeding episodes.