
I have a theory that the younger brother of mc in this new world is actually the sister of mc in previous world. I mean the brother knows the name of the book and I think the sister changed genders because of her trauma from that bitch of a dad, the last chapter implied that she was assaulted by that bastard. So I think this is why she changed genders in new world. Like she got an option while mc was just thrown in new world with ml being reborn with no memories. Just my theory not a spoiler