I just read the book "Slawter" by Darren Shan. The main character, Grubbs, changes quite a lot from the beginning of the book to the end. In the begging of the book Grubbs is sort of living an ordinary life aside from having to take care of his possibly mentally ill uncle who was traumatized by a demon. At the end of the book Grubbs becomes a very powerful mage after narrowly escaping death by a powerful demon master.
