In the Soul Hall hierarchy, the highest authority has always been that of the Elders.
Seven Elders represent the highest decision-making status in the seven halls. A figure like an Elder has a position in World City that is infinitely close to that of Li Hong, the ruler of the World Throne. Even many of the Soul Hall Elders are highly respected, and people on the throne could be their junior counterparts.
So, even the one who achieves the title of King for ten years must show some respect to elders of such level.
Similarly, the status of the Nightmare Demon Palace Elders is like this as well. Many times, when an Elder needs to criticize the mistakes made by the young Demon Emperor, the latter would have to listen with his head lowered.