Lin Biao (5 December 1907 - 13 September 1971) was a Chinese politician and Marshal of the PRC who was pivotal in the Communist victory during the Chinese Civil War, especially in Northeast China from 1946 to 1949. Lin was the general who commanded the decisive Liaoshen and Pingjin Campaigns, in which he co-led the Manchurian Field Army to victory and led the People's Liberation Army into Beijing earning a strong following in his own right.

Lin Biao was born in 1907, making him over ten years younger than Mao. Born to a landlord, his position within the Chinese social structure at the time was comparable to Mao, though Lin was not a part of the peasant class. In 1925, he went to the Whampoa Military Academy after joining the Communist Youth League. During his time at the academy, Lin befriended Zhou Enlai. It was after the split between the KMT and the CCP that Lin and Mao met.

In 1928, Lin became the commander of the Red Army's First Army Group. His men fought against the KMT quite successfully. His army was known for its mobility, and they captured twice the number of prisoners of war and military equipment than the two other groups of the army combined. However, the KMT grew to be too big of a threat, which was when Lin and his men joined the Long March as a part of the vanguard. Lin also fought against the Japanese during the Second Sino-Japanese War, where he sustained a serious injury. Between 1938 and 1942, he received medical treatment, traveling to Moscow for his treatment and recovery. Following the end of the Second Sino-Japanese War, Lin's military strategies against the KMT helped the CCP to rise in power. It was his ideas and prowess that helped the CCP gain the upper hand when they defeated the KMT in Manchuria. In recognition of his brilliant strategies, Lin was promoted to commander of the Central China Military Region.

Lin aided in building the Cult of Personality that ensured Mao would return to power and retain it. To do that, Lin ensured that the military developed a type of reverence for Mao, sending them to a school that followed Mao Zedong Thought, also known as Maoism. He decided to collect quotes and ideas that Mao had expressed over the years and had them compiled into the Little Red Book.

Lin Biao was one of the leading figures under Mao, and for a time, he had even been Mao's chosen successor. They had followed similar trajectories, joining the CCP during the 1920s and fought for them. Like other people who had been under Mao, Lin would become a suspect in Mao's eyes. Despite having spent years developing a bond with Mao and having supported his fourth wife, Jiang Qing, Lin would fall from power because of Mao's paranoia. He died in a plane crash after fleeing China in the wake of a failed coup against Mao.