So here's my opinion. I don't enjoy the story much since it likes the characters are moving on a limited space. Well, it can't be helped since this is following the story path of the original game but it such a waste and some of the readers are not that hooked since the progress are too slow and...
He probably killed her entire family so she would hate him and have a reason to kill him. Probably, those who can only wield the Pamado can kill him. It's not good that he actually needs to kill her family but I can understand the guy's pain.