
becuz she is the real Cayena, after she died in the novel story, she was born in the modern world and happened to read the story of Cayena not knowing that it was her past life.
And now, she's back to being Cayena again after her death in the modern world... including all her memories of being Cayena. And that made her who she is now (smart and brave) so she can survive and avoid her death like the past life Cayena which is her
sorry im not that good th english

I don't think she's trying to ruin Rezef. I think she's genuinely trying to help him and her brotherly affection toward him is real. I think you can only see the pov of rezef at this point, since i bet what you're trying to talk about solely regarding to what his reactions and feelings are. She only thinks of Rezef's wellbeing IN THE LONG RUN. I think the influence that you're talking about is his 'people' but remember that those people WORKED for That other duke too, i think his name is Heindrich (?) That's why Kayena took care of them early.
Okay I’m up to date with this manhwa but there’s so many plot holes in this. First of all, we’re told the female lead reincarnated into the novel world from the normal world but she acts like she is actually the real Cayena and that it’s her second life and she has memories of her first life. Even if that is the case it wasn’t mentioned in the story at all unless I missed something. Second, the male lead’s past is a big confusion too. She said his parents were undergoing a divorce and people suspected the male lead to be gay because he didn’t go near woman when actually he had mysophobia but he also had an affair with her father in law from her first life. This is just so weird and confusing. Third, we have no idea what the FL is even trying to do and accomplish. She says she wants freedom but all she’s doing is increasing her influences and indirectly competing against Rezef. She says she wants to make Rezef emperor when she herself is lessening his influence and increasing his competition. She says she wants to save Rezef and that there’s still hope for both of them yet she’s doing what she can to ruin her relationship with him by constantly stepping on his toes. Forth, Rezef was too quick in getting to like Cayena when he used her like a doll in the past. There are more plot holes as well both big and small. The art is beautiful but the plot is lacking.