Acho que você está atrás de " Eternal ", o segundo livro da " Tantalize "série de Cynthia Leitich Smith;
This dark romance is told in alternating chapters from the perspectives of 17-year-old Miranda and her guardian angel, Zachary. Early in the novel, Zachary falls from grace as punishment for materializing in his full radiance in a failed attempt to save Miranda from being bitten by a vampire.
The tale resumes a year later with the now-vampire Miranda a revered princess living among vampire royalty and feasting regularly on humans. Zachary has sunk into a life of aimless debauchery and is resigned to never regaining his wings".