After the commotion ended, Wei Yusheng didn't delay any longer and left the Eternal Peak to look for a temporary place to stay.
The Eternal Lord, Tian Yongheng, told him to stay away from the State of Feng as a whole to avoid being found out by the Sword Lord of the Darkest Night. If he remained here, he could cause trouble for both himself and the Eternal Peak.
Secondly, it was because Tian Yongheng suspected that the Sword Lord of the Darkest Night probably had a way to track Wei Yusheng.
He won't let the other party off the hook. As long as he entered the Qingyun Region, he would die an unremarkable death in the hands of Tian Yongheng. He won't bother hiding his powers when his life was in danger.
Not to mention that the Sword Lord of the Darkest Night was only at the peak of Tribulation Transcendence Realm.
Tian Yongheng was capable of killing Human Immortals!
