I Became the Young Villain's Sister-in-Law

After being reincarnated as an extra with amnesia, I saved a child by chance, but he was the villain… What? The villain had a brother who died because of a fairy's curse. He was the reason for the villain's corruption. How cruel, if I met that fairy, I would have killed her, but unfortunately I'm an extra... “Elia?” Wait… Am *I* that fairy?