Generally, when proving the Tao and becoming a Saint, such awe-inspiring thunderous sounds would echo above the firmament. However, for Merit Saints, there would be only three thunderclaps, followed by celestial light descending upon the world and auspicious colors appearing above the firmament. The images of those who had become saints would also appear throughout the Three Realms.
However, slaying the Three Corpses to achieve the Dao and become a Saint was different, resulting in the achievement of the Primordial Taiji Da Luo Golden Immortal realm. Above the firmament, nine awe-inspiring thunderclaps would sound, known as the World-Shocking Nine Thunderclaps, just like the current situation.
Any expert with a bit of insight had heard of these World-Shocking Nine Thunderclaps because it was said that when Hong Jun Daoist Ancestor achieved his Dao, such thunderous sounds had appeared.
