i feel bad for the duke, its likely he loved his daughter in the original timeline and went crazy with the suicide, and the dagger was just for self protection.
but man the duke was dumb in the OG timeline imo and did not think in her emotional state and psychology like this one for whatever reason.
she's wrong, even if she try to fix after, when you introduce someone no one knows in a social party like that, you have first to introduce him and find people so that person can talk, and only after that you can leave that person alone to talk to other people, especialy if there's a noticeable...
the duke sucks a lot for letting her go there and decided to take it easy and lawfull, ignoring the traumatic abuse of a little girl, fuck him.
Everyone in this novel except the employee of the duke deserve to die or get a good beating.