|“||It is not that I fear to go out, nor that I relish the insults, but I have the Emperor's command to hold on and may not disobey.||„|
|~ Sima Yi.|
|“||The mind shall vanquish the sword!||„|
|~ Sima Yi's victory quote.|
Sima Yi (司馬懿), style name: Zhongda (仲達), is a Three Kingdoms historical figure who was known to originally be a vassal to the Wei kingdom, helping his Lord Cao Cao in his ambitions as a very brilliant tactian. He then serves Cao Cao's son, Cao Pi. However, it was often stated by Cao Cao that Sima Yi never had much intention of serving below someone, a fact that came to fruition during the aftermath of Zhuge Liang's Five Northern Campaigns against Wei when Sima Yi took control of the falling Wei empire, and went on to establish the foundation of the upcoming Jin dynasty.
He is often considered one of the main antagonists in the later parts of the 14th-century Chinese classic novel Romance of the Three Kingdoms by the late Luo Guanzhong, and its multiple adaptations. Historically, he and Zhuge Liang didn't exactly have the well-established rivalry seen in most fictional accounts. His wife is Zhang Chunhua, while his two historical children are Sima Shi and Sima Zhao.
Sima Yi started serving the Wei forces as a simple vassal, albeit a genius one that puts his allies to shame. He works his way up the ranks, due to his repeated successes and strategies against both of Cao Cao's main rivals, the Shu forces and the Wu forces. After Cao Cao's death, he is appointed as supreme warlord by emperor Cao Pi.
Meanwhile in Shu, the legendary and unparalleled military genius, Zhuge Liang, starts to feel threatened by Sima Yi and begins an expedition into Wei. Cao Pi's vassals advised Pi against Sima Yi taking control of military authority due to Sima Yi's potentially dangerous ambition, but Sima Yi was the only strategist who could match Zhuge Liang's genius on even terms so the emperor of Wei had little choice.
After many battles and years, Zhuge Liang and Sima Yi's rivalry reaches a stand off at the Battle of the Wuzhang Plains. During this legendary battle. Zhuge Liang falls gravely ill, and decides to end the battle quickly. Sima Yi, knowing that without Zhuge Liang the Shu forces are nothing, plans for a long, drawn out battle, hoping for Zhuge Liang's death.
After Zhuge Liang dies, Sima Yi wins the battle but at the same time admits defeat as Zhuge Liang managed trick him one final time before his demise by making him think he was alive, which causing Sima Yi to retreat his army. Although they were rivals, Sima Yi has great respect for Zhuge Liang, and orders a memorial in honor of his fallen rival. A few years later, Shu is conquered as Zhuge Liang is no more to help them and his student and Zhuge Liang's son unable to defend the country due to the foolish ruling of Liu Bei's son, and Wei looks as if it will unify the entire land. However, Sima Yi, along with his sons, see this as an opportunity to overthrow Cao Pi's incompetent son Cao Rui to take power for themselves; as fears of Cao Pi's vassals had come to pass and vindicated.
Although the Cao family is the ruling family, the Sima family are actually the ones that have garnished the most power, including the army. After Sima Yi's dies from poison wind, a Chinese term for a sickness that involves the suffer being weakned overtime and eventually dies, the Sima's sons successfully overthrows the Wei Empire, and establishes the Jin Empire. Seeing that Jin rule is inevitable, Wu surrenders, which is also because of its blundering ruler, Sun Quan's son. China is unified under the Jin Empire.
- Sima Yi appears as one of the playable characters in the Dynasty Warriors video game series.
- Sima Yi is one of the recurring boss characters in the Knights of Valour game series.
- Despite being frequently presented as an Evil Overlord and being spectacularly arrogant, Sima Yi actually has very benevolent philosophies. He dislikes social constructs like divine right to lead or blood succession of rulers, scorns the idea of hiring based on noble standing, and believes in maintaining order by having those with the right talent in power.