I Reincarnated in a Novel

I was an orphan in my previous life. Then I died. But death was not the end for me. I reincarnated in another world. In a rich family. For the first 10 years, I lived a rather peaceful life while learning new things and letting my memories from my previous life settle in my current life. But, then I remembered about a novel, 'Top-Level Player'. That was one of the most popular works in my past life, and I liked reading it quite a look. But the book was not ended before I died. And the world I reincarnated was the same world as the one in the novel. I was neither the protagonist nor the villain. Neither was I any side character that was mentioned in the novel in detail. But in the first chapters, I was talked about. I was the protagonist's friend. But after my awakening, I left the protagonist at the start and was never talked about again. Except for the time when the protagonist took revenge against the faction that destroyed my family. 'But I am different.' I would change the ending. I would write the ending with my own hands. No matter what. Even if it means I have to work with the Protagonist. *** I don't own the cover, the credits belong to the creator. If you want it taken down, then comment.