I Was Born as a Character that Wasn’t in the Original Story

In the novel I wrote, I was born as a character that wasn’t in the original story. She is neither a villain nor an extra, but the older sister of a heroine who originally does not exist. “You want to marry me?” “Yes.” “That’s absurd…” ‘But why the hell do I have to get engaged to the sub-male lead? It’s not me who you should like, it’s my sister! I want this story to go the way I wrote it!’ But he made a wish, crying and begging me. “Please change my destiny.”