Huang Zu
For the next several years, Sun Quan was largely interested in expanding against the Shanyue, hill tribes which controlled the most southern part of China and outside the reach of the Han government, in order to ensure his realm. Sun Quan launched numerous campaigns against the Shanyue. In 206, he conquered the fortress of Shanyue in Matun and Baodun and captured more than 10,000 men. Furthermore, he gradually sought to harass and weaken Liu Biao's key subordinate, Huang Zu (who controlled the northeastern region of Liu Biao's domain) – particularly because Huang Zu had killed his father in battle. He made war on Huangzu twice in 203 and 207. In 208, he was finally able to defeat and kill Huang Zu in battle, and as a result, he obtained the most of the territory of Jiangxia. Soon after, Liu Biao died while Cao Cao was preparing a major campaign to subjugate both Liu Biao and Sun Quan under his control, precipitating a major confrontation.