The Ranger and the Angel

Emily is not like most girls in her home village. She hates staying on the sidelines, and, when offered a job in the Couriers, turned it down to be an apprentice Ranger.
Five years later, she meets with the Archangel Annabel, who has startling news: She is the angel's vessel for this time period, and that she might be the only way to stop a coming war with her father, Mogarath, and Annabel's brother, Lucifer...

I do not own characters or settings....
Minor mentions of blood and gore...but seriously, its Ranger's Apprentice. Also, SPOILERS for Book two of Ranger's Apprentice, and possibly for season 5 of Supernatural