Azief knows why he swing his sword.
But Xi Feng, even though his swordsmanship is one of the top tier martial arts in the world, he did not know why he keeps swinging his sword.
As such, to Azief, the sword lack weight
He keeps wrecked by uncertainty. There is a contradiction to him. And that contradiction made his sword strike light and not heavy
Azief could see what Xi Feng wanted to do and he could see what he will become.
But Azief could not tell him that.
In the end, telling him might change what he will become and it is always important for one to seek the answer to such question by oneself.
Azief could only predict. But in the end, there is a reason why prediction is called a prediction. Because sometimes it did not come true.
Xi Feng had to understand it by himself. whether he become a man crazed killer or righteous swordsman, both possibilities exist for him