I've Become the Little Villain's Sister-in-Law [LF Ver.]

The kid I saved by chance after possessing a character with amnesia turned out to be the villain. ...Huh? The villain had a brother who was destined to die because of a fairy's curse. That was his catalyst for becoming evil. Such unfortunate brothers. If I had met that fairy, I would have given her a piece of my mind, but sadly, I am just an extra...... "Ellia?" Wait... That fairy is me?