At the end of the Sui and Tang Dynasties, Yang Guang, the second son of Emperor Wen of Sui, wanted to seize power and viewed the heavyweights in court as thorns in his side. Li Yuan, in order to avoid disaster, prepared to leave the capital and return home with his entire family. Li Shimin, Li Yuan's second son, was deeply in love with a young woman surnamed Changsun and did not want to leave the capital. However, this young woman was very far-sighted. She advised Li Shimin to temporarily return home, focus on studying, and quietly observe the changes in the world. Li Shimin followed her advice and left the capital for his hometown. On the way, Li Shimin was attacked by Liao Wujie, a hired killer known as the "Top Killer of Luoyang," sent by Yang Guang. In a critical moment, he encountered Qin Qiong who was escorting prisoners. Qin Qiong repelled Liao Wujie and saved Li Shimin. Upon learning that the killer was sent by Yang Guang, Qin Qiong feared trouble and left without saying goodbye. To repay Qin Qiong's life-saving grace, Li Shimin built a temple in his honor as a sign of gratitude. (Years later, when Qin Qiong learned that Li Shimin was such a grateful person, he resolutely chose to follow him.)
After delivering the prisoners to Luzhou, Qin Qiong had his travel expenses stolen and fell seriously ill. He was forced to sell his yellow steed. At this time, he met a forest hero named Shan Xinxiong, who always admired Qin Qiong's character and martial arts, so he generously gifted him some silver. On his way home, Qin Qiong mistakenly thought an innkeeper was a bandit, accidentally killing the innkeeper and committing a crime. He was then exiled to Mount Yan by the local government. Later, due to his relationship with Luo Cheng's father, he became a flag officer under Tang Bi, the governor of Shandong.
Not long after Qin Qiong arrived in Shandong, Yang Guang murdered Emperor Wen of Sui and seized the throne. When he forced Minister Wu Jianzhang to forge an imperial edict announcing it to the world, Jianzhang refused and was killed. This caused Jianzhang's son, Governor Wu Zhizhao of Nanyang, to raise troops against the Sui Dynasty. After Yang Guang ordered Han Dewu to capture Nanyang and granted amnesty across the land, he ascended the throne. Cheng Yaojin, sentenced to severe punishment, was rescued from prison. Seeing that he was a hero, Shan Xinxiong persuaded him to join in robbing the tens of thousands of taels of military pay belonging to King Yang Lin, also known as Koshan Wang. They publicly burned the arrest warrant. Unfortunately, both Shan Xinxiong and Cheng Yaojin were captured again at Huangtu Ridge. Thus, Xu Maogong and other heroes returned to Shandong, rescued the two, gathered in Wagang Fort, and proclaimed Cheng Yaojin as the "World-Mixing Demon King." Together, they crushed multiple campaigns by the Sui army.