Du Fuwei
At one point, he had ambitions to take over the region south of the Yangtze River for himself, but he later chose to submit to Tang, receiving the title of Prince of Wu.
Around this time as well, Du selected 30-odd particularly fierce warriors among his soldiers, and he adopted them as sons, even though he himself was only 17 years old at this point and therefore could not have been much, if at all, older than they were—the first recorded instance in Chinese history of such actions to create familial relations among military men.
Fellow rebel leaders Li Zitong and Zuo Xiangcai (左相才) were also nearby, and Emperor Yang of Sui, then at Jiangdu (江都, in modern Yangzhou, Jiangsu), sent his general Chen Leng (陳稜) against them.
Around this time, Du selected 5,000 elite soldiers and called them the Shangmu (上募, i.e., "the best conscriptees"), giving them special privileges.
Yang Tong commissioned Du as the grand commandant of the eastern forces and created him the Prince of Chu.
Meanwhile, Du was contending for the control of the region with Chen Leng, who took over Jiangdu after Yuwen's departure; Li Zitong, then at Hailing (海陵, in modern Taizhou, Jiangsu); and Shen Faxing, then at Piling (毗陵, in modern Changzhou, Jiangsu) and who claimed the title of Prince of Liang.
In summer 620, Emperor Gaozu changed Du Fuwei's title to Prince of Wu, and bestowed on him the imperial surname of Li.
In spring 621, with Emperor Gaozu's son Li Shimin the Prince of Qin putting the Zheng capital Luoyang under siege, Du sent his generals Chen Zhengtong (陳正通) and Xu Shaozong (徐紹宗), with 2,000 men, to assist Li Shimin in his campaign.
Chen and Xu were able to capture the Zheng city Liangcheng (梁城, in modern Ruzhou, Henan).
Fu resented the treatment but, in response, pretended to no longer care about earthly matters, practicing alchemy with his friend Zuo Youxian (左遊仙).
It was said that Li Fuwei himself was acquainted with alchemy and, as part of the exercise to try to live long, consumed mica frequently notwithstanding the poisons contained therein.
Li Fuwei, fearing that his loyalty might be doubted, requested to go to Chang'an to pay homage to Emperor Gaozu, taking Kan with him.
Meanwhile, in fall 623, Fu, after tricking Wang into surrendering his command and killing him, rebelled, claiming that Li Fuwei had been detained and had secretly ordered him to rise against Tang.
In April 624, Li Fuwei died suddenly—with official sources suggesting that he was poisoned by the substances he was taking as a part of alchemical exercises, but also, in a veiled manner, leaving open the possibility that he was assassinated on Emperor Gaozu's orders.
Emperor Gaozu ordered that Li Fuwei's titles be posthumously stripped, and that his wife and children be arrested and made slaves.
