What his father did counts as abuse, but it doesn't justify the murder of his wife. It doesn't justify any murder, really, but to actually target his own wife just to make his daughter more vicious is particularly vile.Just another prison and exploitation for her. Such a farce.
Oh, poor him, not being appreciated by his father. Therefore he has to screw everyone else over, showing he deserved that treatment.
He's a bit... eccentric.
Not entirely sudden though. He's been mentioned before, and actually shown (as someone clearly sus) in Chapter 10.I really hate when a story suddenly introduces undefeatable antagonists like this. It always feels so forced no matter how the authors dress it up.