Cultivation of Immortality: Start by Picking up the Iron Sword

There is a legend in the Kyushu immortal world... Those who reach the pinnacle of the human world in cultivation can trigger a heavenly catastrophe, crush the void, ascend to the fairy world, and live as long as heaven and earth. Zhang Fan had mediocre qualifications, but when he was sixteen years old, he accidentally got a rusty iron sword and embarked on a long road to immortality...