Records of the Three Kingdoms
Zhu Ran, courtesy name Yifeng, was from Guzhang in Danyang. He was born into the Shi family, a son of Zhu Zhi’s sister, and took the Zhu surname when he was adopted. Around thirteen he studied with Sun Quan, and the friendship lasted. When Lü Meng was dying, Sun Quan asked who could replace him. Lü Meng named Zhu Ran. After the fall of Jiangling, Zhu Ran held that city.
In 222 he fought under Lu Xun at Yiling. The next year Cao Zhen, Xiahou Shang, and others besieged Jiangling. Zhu Ran held it for about six months. The garrison was small and sickness spread. He did not surrender. The Wei army withdrew. He spent the rest of his career on the upper Jing front and died of illness in 249, at sixty-eight. Sun Quan mourned him in plain dress.
Romance of the Three Kingdoms
The novel’s siege of Jiangling includes Zhu Ran. He keeps command while sickness runs through the city, until disease in the Wei camp forces a retreat. The chapters are shorter than the loss of Jing under Guan Yu, but the defense is his scene.
The book makes little of his having been Sun Quan’s schoolmate.
Reference: Wikipedia · Zhu Ran