I Became the Villain's Lost Daughter

I possessed an extra who didn't even have a name in the novel. Her features are black hair and purple eyes that means that she is cursed. And I'm the lost daughter of the villain in the novel?! I thought I was a passing by extra, but she was actually the lost daughter of the villainous grand duke.

"Erita, my beloved daughter." "My precious little sister. I'll protect you."

...Are these the bloody villains I've seen? My father and brother, who people said to be cruel, were too sweet to me. But the villain has a death ending! It was the first time I received love and warmth, and I decided to change the cruel ending of my friendly family since I entered 10 years earlier than the original story. Yeah, I will definitely change my family's future...

"Erita, I love you."

What's wrong with the male lead?