Duke unknowingly has some moves. All he needed was the right woman aka his future wife to use those moves from.
POS Baron, just... leave. I won't ask you to die since you'll most likely suffer from the manipulative cousin's *ss. Really, without any spoilers, I can tell how bad the cousin is. Ivona treated him with kindness, naive of her yes, but she still did. To think, he would manipulate the Baron to his side, only save her when in benefit for him (too many instances to show his ability to manipulate already).
I can't fathom what the Baron saw in him, yeah, he ACTS pitiful but when Ivona becomes disfigured, she's not pitiful enough for you? Knowing your actions caused misfortune to another being ain't tugging your heartstrings, you piece of trash?