FYI, she's Rua's older cousin, and the one who trained MC to be the badass that he is. She even calls it out in the first chapter how him breaking away was gonna cause a lot of chaos. She might even be a greater threat than the Pig.
100% she's a bigger threat.
She's competent and calculating where Rua's impulsive and petulant. And I would bet my lunch money that she is fully invested in getting him back into the family fold, because even if he weren't Rua's fiancé, he's a super powerful asset that she put her own time into training and developing.
And of course, also because she would still be beholden to the patriarch - there's a
chance she personally would let him go free, but doing so would anger the Grandfather and she could be finished for failure.
And I don't know if I'd even believe she would personally side with MC; nothing about her thus far says she even feels differently than the Family, so.
Plus - she trained MC. I assume this means she's as capable as he is.