Sun Jian
Yuan Shao sent Zhou Yu (Renming) to attack Sun Jian, who was returning from Luoyang to join Yuan Shu. In the Battle of Yangcheng, Zhou made a surprise attack on Sun's camp at Yangcheng and captured it. Yuan Shu sent Gongsun Yue (公孫越) to assist Sun Jian in fighting Zhou Yu. Gongsun Yue was killed in the battle even though it was a victory for Sun Jian. Gongsun Zan held Yuan Shao responsible for Gongsun Yue's death and declared war on Yuan Shao, which led to the Battle of Jieqiao subsequently.