The Atmosphere of the Novel is In Crisis (Unofficial English)

I found myself waking up inside a novel written by my older sister. However, there was something off about this story... After my sister tragically passed away in an accident, I was granted the opportunity to fulfill one wish in honor of her good deeds. I chose to experience life as the character she cherished the most in her novel. But instead of becoming the main character, I ended up in the body of Satin, the story's antagonist! And the complications didn’t stop there. Cain, the holy knight who is also the main protagonist, keeps interfering in my life. "Hey, why are you looking at me like that? It's so annoying." "Satin, just don’t talk to me. You might as well just die." Who would have thought that as a child, he was actually like a little kitten—feisty and stubborn?! As I try to uncover the mysteries within this story, certain incidents make our relationship much more complicated... "Satin, I really thought you were dead... So, I was planning to kill everyone..." Kill? Seriously? This is really giving me a headache...