C252 Spring of Spiritual Eye

"I can see some clues. This seems to be the legendary Steel Essence." I also saw it from my sect's Heavenly Master Sect's refining diagram. It says that the Steel Essence is a very good material for refining top grade spirit swords, and your Invisible Sword contains a lot of Steel Essence. Usually, a fist-sized Steel Essence can be used to refine two Flying Sword s