@dedmoroz—
A Japanese author might indeed locate the soul partly in the belly. But, beyond that, there is no reason to deny that it might in part be located in each hand if it is in part located in the belly. Has Aimi lost part of her soul? Well, maybe; but it seems that she will survive. Has Flare lost part of her soul? Well, maybe; but that doesn't mean that she won't survive.
In any case, I don't think that anyone should be completely convinced that Flare or Aimi or any other character will ultimately survive, short of having read the relevant remaining chapters. My point here is that an argument that Flare necessarily cannot survive, because of what seems to have happened to her, has unravelled; the case that she might survive has grown stronger.