A Twist of Fate
The Cullen's left Bella in New Moon, and she was pregnant. She had to go somewhere, so she went to the only ones who would and could help her--the Volturi. Her life changed so much after that. She refuses to kill humans, though she'll drink their blood, as well as Renesmee once she's born. But then a miracle happens--although she's a vampire, she has another child who could be the salvation to all vampires and mankind.