How did Xuan Zang overcome the trials of conquering the demon creatures in The Journey to the West?

The Journey to the West was written by Wu Chengen. It is largely a collection of stories about Chinese legends and folklore. In part of the book, Xuanzang goes on an expedition in search of the Buddha's scriptures. As he travels along the path, he faces a treacherous and troubling journey. He must conquer demon creatures. Xuanzang uses the power of the goddess of mercy to protect himself against the danger of the demon creatures, which helps him to defeat them. After extensive searching, Xuanzang ultimately retrieves the Buddha's scriptures. Consequently, his guardians receive salvation.
The Monkey King is his most useful guardian, however, because he transforms himself into varying creatures and can even change the hairs on his body into more creatures to form an army of warriors that can defeat and conquer the demon creatures. The Monkey can also detect when the demons and monsters are disguised in other forms to know how to help conquer them. Through his help and the help of the goddess of mercy, and other protectors, Xuanzang is able to conquer the demon creatures and monsters that they all encounter along the way toward recovering the Buddha's ancient scriptures, which were thought to be located in the West.