Theme of the way of the shadows

The theme of the way of the shadows is it is wise to be determined. I think this is the theme because Azoth is very determined to kill Rat because it will help himself and his friends. The guy who went to find the duke was determined because first he got pass the guard being presausive. Then the man found the duke's son that is now the duke because he went to battle. The new duke said the only way to talk to him is to duel him, but not to kill. The duke had armor and sword and the man had nothing and under 5 seconds he fliped the duke to the ground and pinned him. I think that is determenation.