They are both of the same bloodline as emperors. One of them went to the battlefield wearing armor, protecting his family and country with his own flesh and blood, and finally became a regrettable "death in battle" in the history books; one of them secretly pursued power in the palace, used his wits to seize the throne, and sat on thousands of miles of mountains and rivers, but could no longer wait for the person who promised to see the mountains and rivers together. An unexpected reunion at a banquet is a foreshadowing of fate. The loneliness at the peak of power is intertwined with the melancholy of being broken on the battlefield. In the end, only "the king controls the world, and I return to the dust."
Purpose: Those who hold imperial power will lose their old friends, those who go to the battlefield will become regretful, and those who hold power will never be able to return.