Idk why the author is trying to make the reader sympathize the woman who tried to sacrifice her unborn children to put curses on her enemies. Make no mistake these are attempts are failed murder suicides. No matter how hurt you are you don't ever try to weaponize your innocent children to slay your enemies. By doing so Mirai stooped lower than the hypothetical Mutsu in her mind.
The author really fucked themselves over by making such a vile creature the 5yr old MC's mother. They can't punish it because Kaya will be hurt even more so they just let it walk around the earth free and unpunished.