After Death, I Possessed the Heroine

My name is Bai Zhi. Only after I died did I realize that this world was just a book, and the heroine in the book was my best friend Song Xiaohe. I was just a stepping stone on her road to success, so stupid. The huge hatred did not dissipate my soul. I followed Song Xiaohe. One day I discovered that I could actually possess the heroine, so I started my road to revenge.