A blade that is there but cannot be seen is the reply that Pendragon received from his journey. He did not know where to even begin as he himself has never seen something like this in all the travels that the has done. He has not even managed to change to his first job class advancement despite being above level 100 already.
He contemplated for days and nights in order to be able to see the blade hidden within the sheath, but he could not. The blade of the sword never appeared to him until he decided to use all the experiences that he has accumulated now.
He learned in the central continent that the sword is just a weapon to kill or protect people. In the west, it is something that is considered as a way for you to survive. In the north, it is something treasured as it carries your dreams for the future.