Cheng Jiao, younger half-brother to Qin's King Ying Zheng, was the son of former ruler Sou Jou and a Qin princess, granting him princely status. His appearance featured dark brown hair often tied back, a pinched face, and royal attire. In youth, he exhibited extreme cruelty and ruthlessness, deeming non-royals inferior and expendable. This manifested in acts like forcing followers into human bridges despite alternatives. His cynicism held that all humans are driven by base desires and greed, an ideology reflecting the philosophy of Xun Zi within the narrative’s context. Resentful over his lost claim to the throne and hating his half-brother, Cheng Jiao rebelled early in Ying Zheng’s reign. He allied with minister Ketsu Shi to orchestrate a coup targeting Ying Zheng’s assassination. The rebellion was crushed by Ying Zheng, Xin, Lord Changwen, and mountain tribe allies, leading to Cheng Jiao’s three-year imprisonment in the royal palace. After release, he pragmatically allied with Ying Zheng against their mutual enemy, the influential merchant-turned-chancellor Ryo Fui. Though openly disgusted by Ying Zheng’s rule, he found Ryo Fui’s potential usurpation intolerable. This alliance strengthened Ying Zheng’s faction through Cheng Jiao’s politically influential retainers. During the coalition invasion of Qin, Ying Zheng placed profound trust in Cheng Jiao by entrusting him with governing the capital, Kanyou, while leading Sai’s defense. This marked a turning point: learning of Ying Zheng’s unification ambition, Cheng Jiao developed grudging respect. He resolved to act as Ying Zheng’s "shield," protecting him from warfare’s moral corrosion and vowing to lead if his brother faltered. This period saw Cheng Jiao mature, displaying enhanced leadership and securing greater loyalty from his followers. Ryo Fui later conspired to eliminate Cheng Jiao by engineering an attack on Tonryuu, residence of Cheng Jiao’s wife, Rui. Lured there, Cheng Jiao was betrayed by his general Ho Kaku, imprisoned, and falsely accused of treason. Strategically, he convinced prison guards to free him by exposing Ho Kaku’s plan to eliminate witnesses and promising rewards. During the escape, he fought alongside allies like Ju Haku and Shukan, revealing unexpected swordsmanship skill despite grave injuries. He freed Rui but stayed behind to hold off pursuers. Enraged by Ho Kaku’s taunts about Rui in their final confrontation, Cheng Jiao killed him but sustained mortal wounds. He perished in Rui’s arms, lamenting his inability to witness China’s unification. His last words urged Xin to become Ying Zheng’s "sword" and "shield," ensuring the king’s steadfastness. Cheng Jiao married Rui, a northeastern Chinese princess, who stayed with him over a decade. His feelings for her evolved into genuine affection, driving his desperate Tonryuu rescue attempt. His relationship with Ying Zheng began with mutual animosity rooted in childhood throne resentment and his mother’s decline. Ying Zheng’s trust during the coalition invasion fostered a complex, unspoken bond. Cheng Jiao’s death solidified his faction’s loyalty, with 90% remaining aligned with Qin versus an anticipated 50% defection. Historically, Cheng Jiao adapts the real prince Chengjiao, who rebelled against Qin in 239 BC and died after surrendering to Zhao. The manga adapts this rebellion into his early arc, while his later narrative role—including his death at Tonryuu—extends his character beyond recorded history.