Asked by the Ancient One

It is neither copper, nor iron, nor steel. It was once hidden under Mount Sumeru. If you don't need to reverse the yin and yang to refine, how can there be no water and fire to temper the edge? Killing the Immortal is powerful, killing the Immortal is dead, and trapping the Immortal glows red everywhere. The changes of the immortals are endless and wonderful, and the clothes of the great gods are stained with blood. In this life, I, Tongtian, want my Four Swords of Zhu Xian to change from being indestructible by the Four Saints to being indestructible by even the Four Saints!!! This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.