He was haunted by Old Villainous Heavens and established the Immortal Demon Grotto to hide from it. He then spent countless years, Epoch after Epoch to find a method to destroy the Old Villainous Heavens.
In the beginning of the Heaven's Will Epoch's Desolate Era, he took out Li Qiye's soul and created the Dark Crow in order to look for the Three Grand Maelstroms in the 12 Forbidden Burial Grounds and Ancestral Earths.
Gu Zun wanted to obtain the Longevity Grass, so he told Immortal Emperor Ta Kong the coordinates of the Immortal Demon Grotto. Ta Kong gathered his legions to attack the Grotto, but was stopped and killed by Black Dragon King, who then lead his own army into the Immortal Demon Grotto to sacrifice Ta Kong's Heaven's Will to retrieve Li Qiye's original body.
Alas, the Ancient Ming used this chance to attack the Immortal Demon Grotto. As a result, Calamity God and Black Dragon King's third body were killed, and Black Dragon Legion was almost completely destroyed. Xiao Shi used a special technique to send the Longevity Grass away to prevent the Ancient Ming from obtaining it, but without the Grass he was fatally injured.
30,000 years later Li Qiye came into the Immortal Demon Grotto and found the dying Xiao Shi. Xiao Shi told him about the battle, and that he hid the Longevity Grass. On his last breath Xiao Shi offered to give the Longevity Grass to Li Qiye if he agrees to take him as adoptive father and name one of his children after him, but Li Qiye refused.