Why was it that in fantasy novels, the Heavenly Axiom was often set as the final BOSS?

In fantasy novels, the Heavenly Axiom was usually seen as the final BOSS because it represented the laws and power of the entire universe, had unlimited resources and abilities, and was the master of all living beings. The Heavenly Axiom often appeared in a mysterious and powerful manner. Not only could it control the fate of the entire world, but it could also change the laws of time and space at will. In the face of the Heavenly Axiom, all the powerful protagonists and forces would feel powerless and in awe. Therefore, the Heavenly Axiom was regarded as the most powerful existence in the novel and the controller of the endings of various stories. In addition, the Heavenly Axiom usually had a supreme authority and power that could destroy all forces that challenged it. Therefore, it became one of the common villains in novels.