The problem facing the Human Race was clear, they lacked a unified sovereign power and a responsible leader.
The saying, "When the forest lacks a tiger, a monkey will proclaim itself king," aptly described the current situation of the Human Race.
At this time, should a Human King emerge, sweeping away all before him, then all the demons and ghosts within the Human Race would vanish without a trace. The Human Race would once again display the majesty of the principal force between Heaven and Earth, awe-inspiring all races, with none daring to offend.
A unified sovereign power would be more conducive to the rule of the Human Race. Take the masters of the Law Palace, for example. The reason they were so arrogant was precisely because, with no Human King and none to suppress them from above, they dared to stir up trouble within the Human Race.