Records of the Three Kingdoms
Lu Su, courtesy name Zijing, was from Dongcheng in Linhuai. Early on he proposed to Sun Quan that Wu hold Jiangdong and wait on the changes of the realm. When Cao Cao came south and Zhang Zhao argued for surrender, Lu Su alone urged war and asked that Zhou Yu be recalled.
After Zhou Yu’s death Lu Su commanded the army and proposed lending Nanjun to Liu Bei, so that Liu Bei would hold the west against Cao Cao. He died of illness in 217. After Lü Meng succeeded him, Wu’s policy on Jing turned from alliance toward seizure.
Romance of the Three Kingdoms
The novel’s Lu Su is loyal and a little simple. He stands between Zhou Yu and Zhuge Liang and is easily read by Zhuge Liang.
The loan of Jing becomes a debt that can never be paid off. In the histories it was an arrangement of the alliance. As soon as Lu Su dies, the book lets Lü Meng begin to calculate against Guan Yu.
Reference: Wikipedia · Lu Su