Crowley
Right, is she doing this alone, because if he's had blood, she's dead.
As for the threats, how serious is it? I mean what would you say if someone took Kol, or he flipped that switch again and hurt people. Maybe she gets him back and it stops or maybe she keeps it up. Either way, she's lost someone she loves and I know a little something about that.
I won't let her hurt him though. That I can promise right here.