I get that Kubaru is a psychopath who wants to control others to get what she wants (she wants drama), but shouldn't she just KNOW that certain actions are inherently evil and shouldn't she withhold herself? Most Psychopaths IRL withdraw themselves from society to restrict harm for everyone else, they are responsible with how they manipulate and gather "dolls". Psychopaths who want drama or "dolls" usually end up working as CEO's or politicians, positions where you HAVE power and you get to play with your "dolls" with the expense of hurting nobody and your actions instead progress society.
Like IRL psychopaths aren't inherently evil, they are just people who lack emotion, empathy, and for this reason they can easily manipulate others who are more emotionally driven. Like Kubaru KNOWS what she is doing is wrong. Sure, she can't feel jealousy or hatred so she will never understand the repercussions of her wrongdoings BUT she can read the faces of others and deduce that what she is doing is just wrong. If she wants power, she is going about it in a selfish way. Psychopaths don't want to cause a scene; they want to work in secrecy.
IMO if MC and Rina REALLY care about Kubaru they should make her seek therapy and she can learn to powertrip effectively without hurting others. SADLY, ik this won't happen and the MC will most likely lose himself to Kubaru and Rina will just watch it all happen. Maybe Rina will lose control and start murdering, I mean I hope not, she is the only neurodivergent in the series aside from Kubaru who KNOWS her well.