It boils my blood when I see family structured like this, the golden child and the scapegoat.
The best thing for Karina is to leave this shitty country behind along with a family who says that they love her, but don't act like it.
Years of resentment won't wash away like Aurora seems to expect.
Cue her flipping a switch like Nadeshiko and turning this unruly wolf into a needy puppy.
Or they'll go the Kagai/Komada route and keep the teasing until one or both crack.