In order to be fully prepared, a Nascent Soul Ancestor needed to be with Saint Emperor Zhao Dutian at all times for protection.
Thus, Zhao Sheng and two others discussed and quickly decided on their roles: Zhao Zhenhai was to stay permanently in the Taiji Palace to ensure the safety of the Saint Emperor.
Qingshan Ancestor and Zhao Sheng acted as mobile forces, always on guard against sudden attacks from the Heavenly Corpse Master and the Ghost Manipulating Young Man, and even more enemies.
Of course, the few were actually not very worried about Zhao Dutian's personal safety because virtually no fool dared to intrude into the Imperial City.
This was because the Imperial City and inner city of Divine City were personally built by their ancestor Zhao Xuanjing. The city had multiple Great Arrays set up, as well as some killing devices unknown to outsiders, which were enough to deter anyone other than True Monarchs from approaching.