From Fallen Syndicate:

The duty of the Twelve Apostles is to seek out and destroy the vampires of this world. Bearing a grudge against vampires and the pure blood who created them, Gilles has successfully passed the first two parts of his exam to become one of the Twelve Apostles. For the third and final part of the exam, Gilles is assigned a partner named Luna and together they must travel to a nearby town and kill a vampire named Alan. Will he pass his exam and become an apostle? And who exactly is this girl named Luna?