On the Pilgrimage Route, there are a total of eighty-one trials, yet in reality, the actual demons Sun Wukong encountered along the way were few in number. Although Buddhism and Heaven both hoped to use the Demon Clan's hands to kill Tang Sanzang, due to Sun Wukong's reputation among the Demon Clan, it led to only a very few demons participating in the eighty-one trials, while more demons or those famous Great Demons kept a watchful attitude.
This resulted in the monsters encountered along the way absolutely not adding up to eighty-one, naturally falling short of the required eighty-one trials. So what to do? Tathagata and the Jade Emperor decided: Shall we each send some of our own people to turn into demons? This way, if they indeed kill Tang Sanzang or Sun Wukong, they can still blame the Demon Clan. Thus, on the Western Paradise Heavenly Road, the monsters encountered were either the mount of a Bodhisattva or the pet of an Immortal.
