In The Dream

She pondered over the possibility and looked at her son again. Di Hao was now at the level of a Golden Immortal, but somehow his progress seemed to have been halted. His abilities should have reached a higher milestone, but it seemed to be bound by something.

"Hao Er, come with me." She wanted to test her son's martial arts, so she took her to the practice arena.

Coincidentally, Mu Feng and the three messengers were also practicing there. They had been really hardworking of late and had all turned into immortals after having experienced a catastrophe. Although they each had the opportunity to ascend to the Upper Bound, they were reluctant to leave their masters. Hence, they all stayed behind. 

The four messengers could imagine the lifestyle and culture in the Upper Bound from the way Gu Xijiu and Di Fuyi described it. If they were to choose to ascend in their current state, they would be considered very low-ranking immortals up there.