I Just Wanted to be the Older Sister that the Male lead Knows

I found myself transmigrated into an R-19 romance fantasy novel, where the male lead’s overwhelming charm stood out. It was a story about two protagonists, who grew up in completely opposite environments, falling for each other so deeply that day and night blurred together. I was just an older sister figure who briefly appeared during the male lead, Rian’s, childhood. Our parents were acquaintances, so we met a few times, but after that, we had no further connection. In the novel, my existence was so insignificant that even my life or death was unknown. I had no intention of interfering with the original storyline, but the moment I saw Rian smile at me, I made up my mind. I wanted to he...