Can I be honest, I've never considered Kath the villain of the story

, I guess you could say she is? but depending on how you look at it, Edwin could be just as evil as her, if not more, depending on your choices.
You can tell Rose you'll accept the deal and help her, and then make sure she loses every week, you can also get her to be in debt with the club when she asks you for money, you can learn about the schemes Samson pulled to fuck Veronicas gym and then never tell her nor do anything about it, you can cheat on Mina right after she has been cheated on by your best friend, you can cheat on Hana after telling her you'll be there for her. (I'm guessing all of these will be possible in the future) And I can't quite think of something really evil you could to do Felicia yet actually

, but you can very well fuck the lives of every single one of these girls.
To me Kathleen is just another character that helps move the strings that make the club work, but is not directly responsable for everything, but who knows, maybe the fact Kathleen rewards us with amazing sex is the reason I don't see her as a villain lol.