Hunt and be Hunted

Twelve years into the past was quite a different place for the Raijinshuu and Laxus. Now that Laxus is an S class mage, the gang can go on much more difficult missions, but when the first mission they take has them finding a young woman coated with battle wounds, the group finds themselves sheltering someone who is not what she appears. Who is she and why is she being hunted?