The Metal Sword Devestator was something that Lin Mu had come up with on the spot. Or more like it felt the most natural to him to do it this way. Swords were innately considered to be of the metal attribute and the Sword Dao gave birth to Sword Qi which was a derivative Qi made from metal spirit Qi and many others.
Since Lin Mu had comprehended the Sword Intent, he didn't need much effort to attach it to the Metal Devastator. In fact, unless he had reached the Advanced level of the sword intent, they would have been unable to create such sword imprints.
They were similar to the Sword Lights shot out by the Centennial Sword Ancestor and were composed of pure sword intent made with a sword. But in Lin Mu's case, it was different. Instead of the pure energy form of a sword light, they had turned into physical imprints that accompanied the metal devastator.
