Lü Fan
In 197, when Yuan Shu declared himself emperor – an act deemed treasonous against the figurehead Emperor Xian of the Han dynasty – Sun Ce broke ties with Yuan Shu and joined other warlords in a two-year-long campaign against the pretender. Chen Yu, who was sent by the warlord Cao Cao to assist Sun Ce in the campaign against Yuan Shu, secretly plotted to destroy Sun Ce from within. However, Sun Ce sensed Chen Yu's intentions and sent Lü Fan to deal with him. Lü Fan defeated Chen Yu in battle and forced him to retreat north.