You have to realize that in this world, the existence of a supreme being can sometimes change many things.
Take Great Da Li for example; their supremacy over other countries is solely due to the presence of a Red Sun Martial Venerate, which allows them to compete with the Great Tang Empire.
Now, a powerful figure who can almost rival Superintendent Ye Daoyuan only maintains a courteous relationship with the crown prince while serving as his swordsmanship instructor.
As the future ruler of the empire, the prince, who is so close with such a powerful figure - a figure who will likely be the top person in the world - is bound to attract envy from many.
In essence, the existence of such a power brings about stability in the prince's position, scattering many thoughts and sparing him from many conspiracies.
With such a supreme fighter by his side, others would think twice before acting against him, and who knows how many will join the prince's faction because of this.
