Yo! I came from the gyutaro book and I wanted to say that I have an idea from the story
So when y/n was young, she had a little brother but he died due to muzan, muzan lie to her saying a human did it making her hate humans even more.
After years y/n has felt hatred, grief, anger(kinda like shinobu) after her brother's death, that cause her to have a inner child, when hiro died she felt her brother's death was happening all over again which allowed her to have a break down again remembering her little brother death.
The reason she didn't like killing kids was because they reminded her that she had a little brother, she even said she would never kill her brother, she felt jealous of daki cause she still had her brother.
Y/n inner child tries to talk to her(about the truth and who she really is) but y/n never listened due to muzan telling her not to if only she knew the truth
If you dont want to do this idea that's ok if you dont understand some things just tell me
