What if Mix was actually "cloned"? The Mix(y) boy is much younger than Mix. And then the transformation from woman to man could have decreased her/his age
And Mykage reminds me very much of Otoha. Being unchosen in love (by Toma), despising wingless creatures, torturing Kagura, etc etc... seems payback for the suffering of 12000 and 24000 years ago.