Alison Robinson
In some ways I've seen this all before, it's not a dissimilar concept to the Inheritance Games series by Jennifer Lynn Barnes, there's shades of Harry Potter, the Belgariad, The Tarot Sequence, the Hidden Legacy, and basically any book/film where someone is plucked from obscurity and, despite their lack of training, turns out to be better than anyone else. But that is too simplistic, with all these it is the storytelling that is key and Benedict Jacka is a master storyteller.