Zhang Yan
By the early 190s, Zhang Yan had formed an alliance with the warlord Gongsun Zan against their common opponent, Yuan Shao. Around this time, Zhang Yan gave shelter to the military official Lü Bu who had previously fled from the capital Chang'an; when the "de facto" regent of the imperial court, Li Jue, offered a reward for Lü's capture, the latter defected to Yuan Shao. In 193, Yuan Shao sent his armies (including Lü Bu and his followers) into the Taihang Mountains to destroy the Heishan bandits under Zhang Yan. The southern hills were overrun, but Zhang Yan managed to fight Yuan's forces to a stalemate and maintained his fief in Changshan. When Yuan Shao grew dissatisfied with Lü Bu and tried to kill him, the officer promptly defected back to Zhang Yan before leaving for the south. In 199, Zhang Yan responded to Gongsun Zan's request for help in the Battle of Yijing against Yuan Shao, but Gongsun Zan was defeated before Zhang Yan arrived.