At first the whole concept of being a warrior is for the apprentice nothing more than a romantic ideal. Then, as he starts to learn, he begins to wonder if the tasks assigned to him are really possible to accomplish.
As a result, the apprentice is no longer as convinced about anything as he was when he first started out. But in his loss of conviction, the apprentice walks neatly into the trap set for him by the nagal. Without even realising it, the apprentice has started to look upon the Warrior's Path as being something of a myth.
The moment the nagal becomes aware of this, he begins to challenge the apprentice's sense of conviction in every way possible, and having no other recourse but to fight back, the apprentice will try his utmost to convince the nagal that he is trying his best.
However, by doing so, the apprentice gets caught up in the myth which he himself has created. Being caught in that myth, the apprentice unconsciously starts living the myth in his efforts to be impeccable, until eventually he has lived the myth for so long, that he becomes the myth.