In Dark Fire Alexa has a big role. Zanna noticed the first sign, Alexa had wings growing out of her back. David tried to tell her that Alexa was an angel sent by the fain to be a beacon of hope in the new beginning. Instead Zanna turned him back and refused to accept it. Later on in the book Zanna notices more. When she was talking to Alexa, Alexa said she remembered something from long ago. David's theory was that she picked her parents. She was a fain that wanted an experience as a human girl and she chose Zanna and David to be her parents.