Fei Yao

Fei Yao is one of Cao Zhen's vassals who assisted his lord in suppressing the third Northern Campaign lead by Zhuge Liang.

Romance of the Three Kingdoms
In chapter 97 of the novel, the Wei Regent-Marshal Cao Zhen was sent by the emperor to reinforce Chencang, which was being held down by Hao Zhao, from being conquered by Zhuge Liang. Jiang Wei, a recent defector from Wei to Shu, sent a letter to Cao Zhen proposing that he lead a large force to meet the Shu forces, feign defeat and flee, luring the enemy to follow them, and when a signal fire behind the enemy army is lit, turn around and catch the Shu command in a pincer attack.

Cao Zhen called Fei Yao to discuss the matter, and he declared that Zhuge Liang and Jiang Wei were tricksters, and shouldn't be trusted. Because of Cao Zhen's refusals to accept those facts, Fei Yao volunteered to take Cao Zhen's place, to which was agreed to. Following through with his volunteer, Fei Yao feigns defeat and flees thrice before being ambushed in succession by Jiang Wei, Zhuge Liang, Guan Xing, Ma Dai, Zhang Bao, and Zhang Yi. Fei Yao is eventually cornered and slits his throat.

Upon hearing of Fei Yao's death, Cao Zhen becomes full of regret.