|“||As the head of the same family as the famous Ou Ki but of the main family. It is rumored that he is equally as talented as Ou ki himself. However due to his dangerous ambition he never received King Sho's favour. It is said that he desires to become a king himself.||”|
— Shou Bun Kun talking about Ou Sen's ambition
|“||Going up against this man always feels like you're under amazing pressure. The reason for that is every single time this general looks at us, it's as if he doesn't even think of us as his own allies.||”|
—Heki talking about Ou Sen's leadership
Ou Sen appears to have a warrior's build and a long goatee. His helmet is unique with its lifelike face on both the back and the visor. A dragon's claw holds the top of the helm and speaks to the wealth the family has as such armor would be costly to make. The armor is black and his cape is white.
Ou Sen is rumored to have a secret desire to become a king. He is described by Ren Pa as someone who cares more for his own life than those of his subordinates or the battle, having no qualm with using troops to his own ends and has personally stated that he only fights battles he believes he can win. Similar to Haku Ki of the Six Great Generals, he is a cautious commander who goes to great lengths to set up an advantage or force opponents into an unfavorable situation.
He seems to be quite stoic and has not been shown displaying much emotion besides some shock when Ren Pa outplayed him on the battlefield. One curious trait which Ou Sen has exhibited is that his ambition often leads him to attempt to take enemy generals alive, seeking to make them his own subordinates.
As the head of the same family as Ou Ki, but of the main family, it is rumored he is equally as talented as Ou Ki himself. However, due to his dangerous ambition, he never received King Sho's favor. Mou Ten calls him the "most dangerous" person in Qin because of his aspiration to become a king.
Ou Sen is first seen as his army conquers the Wei city of Sanbi with only his first wave of troops. Before the Battle of Sanyou started, Ou Sen bested Ren Pa by arriving first on the Rui Plains and taking the high ground of Mount Man for himself. From a hill, he observed his son strike with the vanguard unit before leaving with his troops. He was subsequently pitted against the Wei left army led by general Kyou En of Renpa's Four Heavenly Kings.
As his army fought that of Kyou En's, he pulled back his main army to the rear, then arrives to reinforce commander Heki, by giving him command of 5,000 Qin troops and tasks him with engaging general Kyou En. As he leaves, one of his lieutenants asks if that was a wise decision, to which Ou Sen states that Heki will make excellent bait. He arrives with his main army at the Wei Di to catch Kyou En off-guard, killing the Wei troops stationed on the cliffs and re-capturing the position. Mentioning that defeated commanders can only expect death, he offers to spare both Kyou En and his personal troops if he swears his loyalty to him. He adds that the Wei general will become one of his close retainers and given lands, stating that his "kingdom" needs men skilled at warfare. When Kyou En rejects the offer by shooting at him, Ou Sen orders him taken alive and states that he manipulated the battles to make it seem as though the Wei were winning. He is shocked when his troops are caught off-guard by the appearance of great general Ren Pa and orders the officers to reform his troops, telling them to send word to Heki as well. He retreats with his army out of the gorge, stating that he only fights battles where victory is certain. As Ren Pa and Kyou En chase after his army, they enter a forest in which they discover a soil fortress that Ou Sen built, reminding them of Haku Ki who used to do the same.
At the end of the Battle of Sanyou, when Ren Pa decides the Wei army should retreat, he says one of the reasons for their loss was the untouched army of Ou Sen who was waiting for the right time to strike.
In the Battle of Kankoku Pass, he was matched up against the Yan army of Ordo, consisting of many mountain tribes who excelled in territorial combat and could easily get to Kanyou if they were to defeat Ou Sen, which made his role exceedingly important.
The first day passed with little to no battle between the two armies, as the Yan army did not attack the Qin army that was stationed on the mountain.
On the second day, the Yan army began attacking. Ordo's troops slowly moved into the giant fortress, as they specialised in mountain combat. As they were beginning to unleash stronger attacks, an envoy from the Coalition Army HQ arrives and informs them that they need to preserve their strength and utilise attrition warfare. Due to this, the Ordo army backs out of the mountains.
At the beginning of the 15th day, when a messenger informs the officials in the court of the situation on the battlefields, he says that Qin's messengers have completely lost contact with Ou Sen and his army. Shou Bun Kun says that it is possible Ou Sen has simply ran away, as his ambition is to become king and has no interest in losing his life protecting Qin.
The true reason for Ou Sen's retreat was due to Ordo's troops striking the centre of the Ou Sen army, which was responsible for sending reinforcements to the other forts. After they lose their centre fort, the Ou Sen army retreats northwest. Making use of this, Ordo and his army begin pushing in to the mountains, and reach the mountain that leads them behind the walls of Kankoku Pass. The reason Ordo was able to navigate so well in the mountains was because he was a king of 50 mountain tribes, and had superb mountain reading skills
As he and his army reach the cliff, they begin climbing, however not knowing that Ou Sen and his army are right behind them. Ou Sen's army releases a barrage of arrows that take Ordo's army by surprise. Ordo rethinks how its possible for Ou Sen to catch him off guard, and realises that his army never moved northwest, but waited to ambush them.
Ou Sen tells one of his lieteunants, Mouchi to rapidly fire arrows not worrying about ammunition, because they have a good chance of wiping out a big part of Ordo's army, At the same time, he sends Mou Ryuu to capture Ordo and bring him alive. Mou Ryuu and a couple more soldiers quickly set out and reach Ordo, but Mou Ryuu gets killed easily. Qin reinforcements come and manage to hit Ordo with some arrows. Ordo and his army retreat and escape Ou Sen, but his 8000 mountain tribe soldiers that were the core of his army were slaughtered.
He was placed as the supreme commander of the western Zhao attack army. With the generals Kan Ki and Yo Tan Wa as commanders of the 1st and the 2nd army. On the march to Kinan, he orders his men to stop, because, he realized, that it is soon going to rain. with this he saved their energy for their march against time in order to attack Gyou, before the Zhao could rally their defenses.
At the commander meeting in Kinan, he informs the officers that they will be setting out in this night and if one squad should fall behind, the officers responsible for this squad would be executed.
It was revealed that Ou Sen realized that Retsubi was in fact a trap devised by Ri Boku. The city was intentionally designed to be weak and easy to take. Because of the necessity to use Retsubi as a steady supply line for their siege of Gyou, this essentially ruined Shou Hei Kun's strategy. Knowing that, Ou Sen left Retsubi with a small group of bodyguards to scout Gyou. After taking a look on the city, he realized that it was perfectly fortified. With no other options, Ou Sen immediately started devising a new strategy on the spot while his bodyguard protected him from Zhao Patrols. He eventually returned to Retsubi to gather all of the troops to push further into Zhao, declaring that the war will become a battle of wits between himself and Ri Boku.
His strategy was composed of 4 stages: first, completely abandon Retsubi and charge upon other cities. Secondly, use Yo Tan Wa Army as shield to Kou Son Ryuu and his army, then use other forces, like Hi Shin Unit, Gaku Ka Unit, Gyoku Hou Unit, Kan Ki Army and other forces to siege cities and evict the villagers and force them to Gyou. Finally, when all his plan accomplished, he will siege Gyou when the time's right. Ri Boku was horrified when he learnt that refugees are flooding Gyou and he cursed Ou Sen under his breath.
When Ousen got to Gyou, he started to explain the full scope of his plan by stating that there are only two Zhao armies capable of liberating Gyou, which are Atsuyo and Ryouyou armys. Ousen later stated that the army that Yo Tan Wa was facing were the Ryouyou army. Then he split his army further to face the Atsuyo Army while starving Gyou and sending the Heki Army of 8000 men plus 2000 men from Kan Ki Army reserves help to Yo Tan Wa . Also, Ousen left the Kan Ki Army of 60000 men to starve Gyou; surrounding it from getting any help and the Ou Sen Army of 70000 men in addition to 8000 of the Hi Shin Unit , 5000 of the Gyoku Hou Unit and 5000 of the Gaku Ka Unit .
During the Battle at Shukai Plains he position Mou Ten and the 5000 Gaku Ka Unit on the left while putting Ma Kou and the Hi Shin Unit in the center and A Kou and the Gyoku Hou Unit on the right. Later during the battle he tasked Shin with 800 men to kill Ki Sui.
|Dark ambition: 100|
|Ambition: secretly 100|
Ou Sen has been stated to give off an immense pressure with his skills considered to be on par with the Six Great Generals of Qin. His talent was so great that it was even acknowledged by Ko Shou who stated that Ou Sen's strategical acuity was on par with the Six Great Generals even many years before beginning of series.
He seems to have a great level of insight and ability to predict his opponent's moves. Appearing defensive and cautious, he typically utilizes traps to take down his enemies in the form of a sudden surgical strike. Due to Ou Sen's cautious nature, his tactics shared many similarities to Great General Haku Ki's warfare.
During the Sanyou Campaign, he effectively conquered 8 cities over a span of 2 months, besting both Mou Gou's conquest of 3 cities and Kan Ki's of 5 cities by using a lightning fast series of offensives.
Ou Sen has demonstrated impressive terrain manipulation since he was able to direct Heki to use a Wei Di against Kyou En and had captured the important high terrain prior to the battle but a more impressive example is against the Yan army where he was able to use the mountains to such an extent that the opposing mountain tribesmen were amazed that he was a plain dweller and yet he was able to manipulate Ordo, a renowned mountain battle specialist, into a deadly trap. In both the Wei Campaign and Battle of Kankoku Pass, he also demonstrated a rare talent for building strong natural fortresses with a penchant for using the high ground. Ren Pa commented that Ou Sen's fort do not possess even a single opening, which makes it extremly hard to conquer.
Ou Sen also possesses a staggering insight for battle and the tactics utilized by his opponents, often turning their strength against them. Kyou En's offence was blocked by allowing him to advance to the Wei Dei, after this failed due to Ren Pa's intervention the strategic positioning of his core army in the fort created a safeguard and certain countermeasure to Ren Pa being able to regroup his forces after assaulting Mou Gou's base camp. Ou Sen also allowed his forts to be taken at the battle of Kanyou in turn surprise attacking Ordo and wiping out the core elite of his army. Knowing Ordo would not counter attack Ou Sen was also able to successfully counter Ka Rin's elite forces striking at the back of Kankoku Pass.
- Wikipedia lists him ("Wang Jian"), as one of the four generals "commonly known" as the greatest generals of the Warring states period. That's alongside Ren Pa ("Lian Po"), Ri Boku ("Li Mu") and Haku Ki ("Bai Qi").
- Ou sen is credited for Ying Zheng's (Ei Sei) unfication, more than any other general. his actions were directly responsible for the collapse of more than one kingdom.