Just from what he said, when he finally seized the Small World to take refuge from disaster, it happened to coincide with a "Great Tribulation" that affected all heavens and earth. This left you somewhat baffled, because among the books you had read, the only Great Tribulation truly worthy of being called a crisis for all Thirty-Six Heavens was the era of "Great Darkness."
Yet judging from the circumstances Zhang Zhengyang described, it was not the Great Darkness upheaval you knew of...
With Zhang Zhengyang's Immortal King Third Realm cultivation, he had originally been considered a prominent figure even in Qingming Hetong Heaven. At such a time, he should have stepped forward alongside the others to face the crisis. Yet he ultimately chose not to do so. He had never joined any faction and could be considered a Rogue Cultivator.
The hardships and struggles along the way had tempered his temperament greatly, but at the same time, little humanity remained in Zhang Zhengyang. He cared nothing for the lives and deaths of others, so he chose to hide from the disaster, vainly hoping to escape this calamity.
Precisely because of this, Zhang Zhengyang did not know the specific details of this "Great Tribulation" and had little to tell you. However, from his account, he had ultimately escaped the calamity unharmed.
Yet this act completely ruined his reputation. Qingming Hetong Heaven was also a righteous world, and countless people spat upon him in contempt.
Left with no other choice, Zhang Zhengyang cultivated a secret art he had obtained from the Great Void Realm. It was called the One Qi Separating Spirit Technique and had three levels in total. Once cultivated to its highest realm, it could divide into three incarnations.
However, with Zhang Zhengyang's cultivation, he could only cultivate the first