In the The Journey to the West, why did the Jade Emperor in the sky order the Dragon King to rain, and the Dragon King broke the law and asked Cao to levy it?

Ming Jun, an ancient loyal minister, will be an official in heaven after his death, or he is a god. Kevin·Z was still alive when he cut the dragon, so he certainly didn't work in heaven. As for why he should be asked to cut the dragon, I think: Although the dereliction of duty of the Dragon King is blaspheming the position of heaven, the Jade Emperor also wants all people to sacrifice, so it is definitely inappropriate for Emperor Taizong to find someone who has great influence among people to cut the dragon. There is no difference between the emperor and the jade emperor, and no one can order anyone. As prime minister, Wei Zhi is the first choice.

King Jinghe alluded to Li Shimin's brother. Although there is no right or wrong in politics, in order to calm the world public opinion and make the historical record clean, he gave his younger brother a charge and asked Kevin·Z to kill him. In this case, Li Shimin can get away. First of all, it was not him who killed his brother, but the prime minister; And his brother did have his sins, so the story written in The Journey to the West should have been circulated in the Tang Dynasty.