Ax went from a borderline-brainwashed dogma-following wannabe hero living in his brother's shadow, eager to get into the war for the guts and glory but unwilling to make his own decisions, to a mature, thoughtful adult capable of making his own decisions, capable of saying no to authority and standing up for himself, and understanding of the reality of war. I'd argue he actually made some of the largest jumps in terms of development.
