Wang Jian, known as Ou Sen, holds the rank of Great General in Qin's military and leads the noble Ou family's main branch. He is cousin to the late Great General Ou Ki and father to Qin general Ou Hon, sharing an extremely distant relationship with his son that fuels unconfirmed rumors of another man's paternity. His wife, Shu Kei, is deceased. In all known appearances, he wears a helmet and mask revealing only his lower face, characterized by a strong jaw, black mustache, and long goatee; his narrow eyes remain observant and emotionless. His distinctive black armor features a helmet adorned with Asura or deva-like faces, paired with a white cape in the manga or a red cape in the anime. A veteran of decades in Qin's campaigns, dating back to the Six Great Generals under King Sho, his talents earned strategist Ko Shou's acknowledgment but never King Sho's favor due to his ambition to establish his own kingdom. He openly confirmed this ambition by inviting enemy general Ri Boku to join him during the Battle of Shukai Plains, a promise that initially drew his subordinate A Kou to his service. Cautious and calculating, he prioritizes winnable battles and avoids unnecessary risks. He pragmatically sacrifices soldiers to achieve objectives yet prohibits harming civilians in captured cities under penalty of execution. He frequently captures enemy commanders alive for recruitment, exemplified by his offer to Kyou En during the Sanyou Campaign. His tactical approach emphasizes meticulous preparation and psychological manipulation. Before the Chu campaign, he repeatedly demanded material rewards from King Ying Zheng to display petty ambition and alleviate treason suspicions. He feigned inactivity for a year during the Chu invasion to lull the enemy before launching a decisive assault. Historically, he conquered Zhao, Yan, and Chu, the latter campaign mobilizing over 600,000 troops to defeat General Xiang Yan and Lord Changping at Shouchun. In specific engagements: During the Sanyou Campaign against Wei, he secured Mount Man's high ground pre-battle, observed his son Ou Hon's vanguard actions, and strategically retreated when confronted by Ren Pa, luring Wei forces into a pre-built soil fortress. In the Coalition Invasion, he defended Qin's mountain passes against Yan's Ordo, temporarily withdrawing without explanation—sparking abandonment speculation—though his true intent was preserving strength for a decisive counterstrike. At the Battle of Shukai Plains (Gyou Campaign), he faced Ri Boku's forces. After initial setbacks, including a near-fatal flanking maneuver, he refused retreat until the situation became untenable. He later claimed to Ri Boku that he knew a weakness to defeat him anytime but chose not to exploit it, seeking recruitment instead. His victory at Gyou was partly attributed to the Hi Shin Unit's unexpected combat effectiveness.