According to Qin Mu's experience, traveling back to the past through the fog in the Surging River only gave a 'half-day' of time. This 'half-day' didn't refer to twelve hours. It wasn't a precise timing, and instead, it was the darkness replacing the light.
There was no darkness in the celestial heavens, and it was always bright like daytime.
When they come here, no matter how much time passed, it would still be daytime. As long as night didn't arrive, it wouldn't even be a half-day.
When Earth Count made a move, that would be different.
The darkness of Youdu shrouded the celestial heavens and caused the darkness to descend in an instant, thus achieving the requirements to return to the future.
In the darkness, Qin Mu waved at Zhu Que'er and Celestial Venerable Ling. He, Founding Emperor, and the old bull's figures were like pitch-black sand drawing in the flowing darkness, scattering with the wind.
