The Monkey King once became sworn with six lich kings. Why did he only meet Niu Wangmo on the way to learn from the scriptures?

The Monkey King once became sworn to six demon kings, but he only met Niu Wangmo on the way to learn from the Buddhist scriptures, because these demon kings' territory was not on the way to learn from the Buddhist scriptures, which was not conducive to the development of the plot, and these demon kings were either eliminated by heaven or appeased by the Buddha. Before studying Buddhist scriptures, Wukong was very popular in Huaguoshan. At that time, he had many small fire companions and made many demon kings, such as ox essence, lion essence, monkey essence, Niu Wangmo and so on. They are all leaders in various fields, but did the friends find that when they got to the Buddhist scriptures, these demon kings disappeared? Next, I'll explain the mystery to you.

The Monkey King was sworn to six Lich Kings. The reason why he only met Niu Wangmo on the way to learn the scriptures was because their territory was not on the way to the west. Although these lich kings have great influence, they only appear next to Guo Huashan. On the way to learn the scriptures, only cattle's territory can pass through, and it also belongs to the sphere of influence of cattle. So I seldom meet those lich kings on the way to learn from the scriptures. This is one of the reasons.

The reason why I only met Niu Wangmo on the way to learn from the scriptures is because it is conducive to the development of the plot. On the way to learn from the scriptures, I encountered eighty-one difficulties. In fact, I read it with a rifle. What difficulties they set on the road are all to test their sincerity in learning from the scriptures. Among them, Niu had a son named Hong Haier, and this ordeal was also to test the four monks and mentors of the Tang Dynasty. Moreover, the monsters that Tang Priest and his disciples encountered along the way were all descended from heaven and had certain control ability. If those demon kings are allowed to appear on the way to learn from the scriptures, there may be some uncontrollable situations. Therefore, in order to adapt to the development of the plot, those demon kings can't appear on the way to learn from the scriptures.

If you have any good ideas about these things, please write them in the comments. Let's discuss them together.