True and False Daughter

I am a fake daughter, and have been the daughter of that family for more than ten years. When I was fifteen years old, I knew that I was being carried by the wrong person. When my father took me to business gatherings several times, I always felt a pair of eyes looking at me. When I was twenty-one, the real daughter came back. How could I see in her timidity that she was not simple? Can we become an ally? Yes Can you help me? There is a maniac in this family who is obsessed with an older brother than me. I pretended to be this identity or he found out and told me that on the surface I am his sister, but behind the scenes I am his lover. I need his hand to help me climb up. I also need him to get rid of the family and let him become a lamb to be slaughtered. No one in this family is a good person. They are born to be bad to the core, which makes people disgusting and boring. This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.