Shi Ren was a military general serving under the warlord Liu Bei in the late Eastern Han Dynasty.
Shi Ren was from Guangyang (southwest of present-day Daxing District, Beijing). He served at Gong'an in Jing Province, under Guan Yu, who was appointed by Liu Bei to guard Jing Province. Following a dispute with Guan, Shi and Mi Fang defected to the warlord Sun Quan when Guan was away at the Battle of Fancheng. Shi and Mi allowed Sun's forces to overrun Jing Province, leading to Guan's defeat and death.
In Luo Guanzhong's historical novel Romance of the Three Kingdoms, Shi Ren's name was wrongly written as "Fu Shiren" (傅士仁). Despite this misspelling, his role is relatively consistent with history.
After Guan Yu was given orders to invade Fancheng, he appointed Shi Ren and Mi Fang as leaders of the vanguard. That night, a fire broke out in the vanguard's camp. However, Shi and Mi were too busy feasting to notice and the fire engulfed and destroyed much of the camp. Guan condemned the two generals for lack of care and sentenced them to death, but was stopped by Fei Shi who advised Guan against executing a general before the army had truly begun to march. Guan took the advice and instead flogged them forty times each. He then called upon Guan Ping and Liao Hua to replace them as van leaders and sent the two generals away, Shi Ren to Gongnan and Mi Fang to Nanjun.
After Sun Quan captured Jingzhou, he sent Yu Fan, a childhood friend of Shi Ren, to Gongnan in order to convince Shi to defect. Upon hearing of Yu Fan's approach, Shi Ren closed the gates of Gongnan and refused his friend entrance. Still, Yu Fan managed to contact Shi by attaching a letter to an arrow and firing it over the city walls. Upon reading the letter, Shi opened the gates and allowed Yu entrance. The two talked like old friends and Yu convinced Shi of Sun Quan's greatness, causing him to join Sun's army. After this, Lü Meng sent Shi Ren to Nanjun to convince Mi Fang to defect as well. Mi Fang was hesitant to desert Guan Yu, but once a messenger arrived in Nanjun and demanded rice for Guan's army in Fancheng, threatening punishment if Mi disobeyed, Shi Ren slew the messenger and Mi, fearing Guan Yu's response, defected to Sun Quan's side.
During the Battle of Xiaoting, Shi Ren and Mi Fang overheard their soldiers discussing a plan to kill them, so they assassinated their superior Ma Zhong and attempted to return to Liu Bei's side. Liu refused to accept their surrender and handed them over to Guan Yu's son Guan Xing, who executed them.