Initially loyal to warlord Yuan Shu, Lei Xu abandoned his master when the latter's regime collapsed, becoming an independent bandit.
[2] Yuan Shu had declared himself "emperor of Zhong" in 197, resulting in a coalition of other warlords taking up arms against him.
[2] By 200, Lei Xu, Chen Lan, and Mei Cheng were operating as bandits from Lujiang, using their dissident armies to plunder the area between the Yangzi and Huai River.
[4][6] However, the rebel leader survived and still commanded a sizable force of followers; he fled westward and submitted to Liu Bei.
The Records of the Three Kingdoms reported that Lei then settled in Jing Province with tens of thousands of followers, but sinologist Rafe de Crespigny considers these numbers to be an exaggeration.