|Officer of Lü Bu|
In historical records
Cao Xing was a subordinate of Hao Meng, an officer serving under Lü Bu. One night in the sixth lunar month of 196, Hao Meng started a rebellion against Lü Bu in Xiapi (下邳; present-day Pizhou, Xuzhou, Jiangsu), the capital of Lü Bu's domain Xu Province, and attacked Xiapi's administrative office. Lü Bu escaped from the office and went to the camp of his subordinate Gao Shun. Gao Shun led his soldiers to Lü Bu's office and drove away the rebels, who fled back to their own camp.
Cao Xing refused to betray Lü Bu so he turned against Hao Meng and fought with his superior. During the fight, Hao Meng injured Cao Xing with his spear, but Cao managed to cut off one of Hao's arms with his sword. By then, Gao Shun had shown up to attack Hao Meng's camp and he beheaded Hao. Cao Xing was placed on a stretcher and sent to Xiapi to meet Lü Bu. Lü Bu asked him, "Hao Meng was instigated by Yuan Shu. Who else was involved in the plot?" Cao Xing replied, "Chen Gong is an accomplice." At that time, Chen Gong was seated nearby and he gave an obvious angry expression when his name was mentioned. Lü Bu felt that Chen Gong was his key advisor so he refused to believe the accusation. Cao Xing said, "Hao Meng often urged me to rebel also, but I said that you, General, are like a god and cannot be defeated. Unfortunately, Hao Meng refused to believe what I told him." Lü Bu then exclaimed, "You're a true soldier!" He treated Cao Xing well and placed the latter in charge of Hao Meng's men after the latter had recovered.
In Luo Guanzhong's historical novel Romance of the Three Kingdoms, Cao Xing played a greater role in the events preceding the Battle of Xiapi in 198. Cao Xing and Gao Shun were sent by Lü Bu to defend Xiaopei (小沛) from Cao Cao's general Xiahou Dun. When the two armies met outside the city, Xiahou Dun duelled with Gao Shun for about 40 or 50 rounds before Gao retreated. While pursuing Gao Shun, Xiahou Dun was hit in the left eye by an arrow fired by Cao Xing. With a cry, Xiahou Dun pulled out the arrow along with his eyeball. He exclaimed, "Essence of my father, blood of my mother, I cannot throw this away!" He then swallowed his eyeball and charged towards Cao Xing and impaled the latter right in the face with his spear. Cao Xing fell off his horse and died.
- (建安元年六月夜半時，布將河內郝萌反，將兵入布所治下邳府，詣廳事閤外，同聲大呼攻閤，閤堅不得入。布不知反者為誰，直牽婦，科頭袒衣，相將從溷上排壁出，詣都督高順營，直排順門入。順問：「將軍有所隱不？」布言「河內兒聲」。順言「此郝萌也」。順即嚴兵入府，弓弩並射萌衆；萌衆亂走，天明還故營。) Yingxiong Ji annotation in Sanguozhi vol. 7.
- (萌將曹性反萌，與對戰，萌刺傷性，性斫萌一臂。順斫萌首，牀輿性，送詣布。布問性，言「萌受袁術謀，謀者悉誰？」性言「陳宮同謀。」時宮在坐上，靣赤，傍人悉覺之。布以宮大將，不問也。性言「萌常以此問，性言呂將軍大將有神，不可擊也，不意萌狂惑不止。」布謂性曰：「卿健兒也！」善養視之。創愈，使安撫萌故營，領其衆。) Yingxiong Ji annotation in Sanguozhi vol. 7.
- (卻說夏侯惇引軍前進，正與高順軍相遇，便挺槍出馬搦戰。高順迎敵。兩馬相交，戰有四五十合，高順抵敵不住，敗下陣來。惇縱馬追趕，順遶陣而走。惇不捨，亦遶陣追之。陣上曹性看見，暗地拈弓搭箭，覷得真切，一箭射去，正中夏侯惇左目，惇大叫一聲，急用手拔箭，不想連眼珠拔出；乃大呼曰：「父精母血，不可棄也！」遂納於口內啖之，仍復挺槍縱馬，直取曹性。性不及提防，早被一槍搠透面門，死於馬下。兩邊軍士見者，無不駭然。) Sanguo Yanyi ch. 18.