Zhu Bajie (Pigsy), also known as Zhu Wuneng or Zhu Ganglie, was originally Marshal Tianpeng in the Heaven. However, after getting drunk and flirting with Chang'e, the Moon Goddess of the Guanghan Palace, he was punished by the Jade Emperor and banished to the mortal world.

The Pig Yaoguai

When he was banished to the mortal world, Bajie intended to possess a human body to reincarnate (by killing someone and taking over their body, which supposedly would allow him to retain his memories). However, due to a mishap, he ended up in the womb of a sow. Although he retained his memories, he also took on the appearance of a pig. Enraged, he killed his pig mother and siblings upon birth. Thereafter, he became a Pig Yaoguai, living off the mountain and eating humans.

Later, the mistress of Yunzhan Cave on Fuling Mountain, Lady Egg, noticed his martial skills and took him as her husband. However, she died within a year, and the Pig Yaoguai inherited the cave, continuing his bandit ways. Despite his previous life's memories, he felt guilty and longed for redemption.

Enlightenment by Guanyin

One day, the Pig Yaoguai saw a white figure flying across the sky. Upon closer inspection, he realized it was Guanyin. He blocked her path and explained his story, seeking her help to escape his downfall.

Guanyin asked, "Why do you continue to commit sins if you were banished for violating the Heavenly Court's rules?"

The Pig Yaoguai replied, "All the Yaoguais in the mountains live like this. If I don't kill and eat, I'll starve."

Guanyin responded, "If you truly wish to do good, Heaven will help you. The world has grains that can fill your stomach. Why must you eat humans?"

Awakened by her words, the Pig Yaoguai bowed and said, "I want to walk the right path, but I've committed too many sins. I'm afraid there's no way back."

Guanyin said, "I have a mission to find a pilgrim to fetch scriptures from the West. Would you be willing to be his disciple and accompany him on this journey to atone for your sins?"

Overjoyed, the Pig Yaoguai agreed. Guanyin gave him the Buddhist name Zhu Wuneng and instructed him to abstain from five meats and three pungent vegetables, and wait in the mountains for the pilgrim.

Gao Village

While waiting for the pilgrim, Zhu Wuneng didn't remain idle. He transformed into a human, named himself Zhu Ganglie, and became the son-in-law of Gao Village. The village head, seeing that he had no family, took him in as the husband of his third daughter. Zhu Ganglie worked hard, plowing fields without oxen and harvesting without tools, doing the work of dozens. However, he had a massive appetite, needing hundreds of buns per meal.

When Tang Sanzang and Sun Wukong passed by Gao Village, they learned of a Yaoguai there and offered to help. After hearing the story, Sun Wukong commented, "If he does the work of dozens, what's wrong with eating a bit more?"

The village head explained, "It's not just his appetite. His appearance changes! After staying with us for a while, his ears grew larger, his nose elongated, and bristles appeared on his neck. He turned into a pig."

It turned out that after achieving his goal, Zhu Ganglie stopped using spells to hide his true form. The Gao family, initially terrified, sought help to expel the Yaoguai. Angered by this, Zhu Ganglie locked the third daughter in the backyard, preventing anyone from seeing her. To avoid the exorcists, he moved about only at night.

Sun Wukong rescued the daughter and disguised himself as her, waiting in the room for Zhu Ganglie. When Zhu Ganglie returned at night, Sun Wukong pretended to be unable to walk and asked to be carried. After some antics, Sun Wukong subdued him (this scene is often humorously depicted in adaptations; you can search "猪八戒背媳妇" for more details). Upon recognizing Sun Wukong, Zhu Ganglie revealed that he had been enlightened by Guanyin and was waiting for the pilgrim.

Conversion to Buddhism and Journey to the West

Subdued by Sun Wukong, Zhu Wuneng revealed his encounter with Guanyin and his mission. Sun Wukong, upon hearing his story, brought him to Tang Sanzang. After explaining the situation, Tang Sanzang accepted him as his second disciple. The Gao family was also relieved to be rid of the Yaoguai.

When introducing himself, Wuneng mentioned that he had abstain from five meats and three pungent vegetables. Tang Sanzang then gave him a new name, Zhu Bajie:

• Zhu (猪): means pig
• Ba (八): means the number 8 (referring to abstaining from five meats and three pungent vegetables, totaling 8)
• Jie (戒): means abstain

Thus, Bajie means "abstaining from eight kinds of food."

After bidding farewell to Gao Village, Zhu Bajie joined Tang Sanzang and Sun Wukong on their journey to the West...