I hope the dad will reflect on the fact that regardless of revenge, what he's doing with Karma is messed and his daughter would disapprove. He's essentially using a girl that clearly need help and got fucked up by North Korea as a tool and he clearly has no consideration for her as a human, when she did nothing wrong as far as he's concerned.
That's unlikely. He knows fully well what he's doing, and he even said in this chapter that he's stopped believing in heaven and he's doing this more for himself than for his daughter. The vice-chairman has already sold himself to the devil, now he just wants to sit and watch as the bullies burn.
He wants them to experience the same suffering and despair that she did. He wants to destroy their futures and completely strip them of hope, to the extent that even if they wanted to choose death like his daughter, they wouldn't even be able to.
I think
Plaything is a fitting title for this story, as it somewhat applies to both Karma and the Vice Chairman. They both see the bullies as pawns on a board, toys that can't leave the playing field until they're done with them.
Even Karma is a chess piece and she's fully aware of it. Her adoption was more like a business transaction. He basically hired a teenage assassin. She gets playthings to torture without needing to worry about the consequences and he gets to achieve his perfect revenge. He never intended to "fix" her in the first place, as having a person who literally lacks emotions except when she inflicts pain on others is more beneficial to him right now.
Maybe he might actually have a heart to heart with her after his revenge is complete (assuming she doesn't betray him and go off the rails), but I wouldn't put my hopes up on him having some sort of redemption arc anytime soon. He probably might just give her a bunch of money and promise to cover up any incidents she makes in the future.