Hai Rou is one of the 100-Man Commanders of the Hi Shin Unit.
Hai Rou has short spiky grey hair, along with a beard. While on the battlefield, he wears armor.
He is first shown with his squad mocking Taku Kei’s squad. Shin then catches his eye, and they almost get into a fight. But then they are ordered to get into formation because a 1000-man Commander is passing through. When Shin steps out of formation, he is surprised that he is friends with the 1000-Man Commander.
Then their destination is moved from Asui to Dakan Plains. Five days later, they find out from Heki that the Wei have launched an offensive from Keiyou in an effort to catch them off-guard. In response the Qin forces have advanced from Asui to Dakan Plains to meet them.
While being split up, they are put in Baku Koshin’s unit.
When they charge the Wei the use the Rock formation, Hai Rou tells his squad to use the corpses from the people who are killed to overcome the defensive wall. Otherwise they will be crushed to death between the Wei and everyone behind them. But Shin runs to very front and jumps over the wall killing a great number of Wei and opening a path for the Qin.
During the Battle at Dakan Plains Taku asks Hai if his squad has seen Shin and Kyou Kai? He responds by saying he must have went further into enemy lines.Then he asks Taku who he is? He tells him he’s not sure, and he thought he was a pretty strange boy, but on a fundamental level, he’s completely different from them.
After they survive the chariots, they help the Taku Squad make ramparts by piling up dead bodies. They survive the 2nd Wave. But during the 3rd Ei is killed by a javelin. Shin pulls it out then jumps and kills a chariot driver, knocking it over the whole chariot unit.
When the 2nd wave comes back from the opposite way, Shin comes back riding a horse. Shin then goes to buy then some time to expand the barricades.
As the few survivors are about to get attacked by the Wei infantry, they are saved by the cavalry.
With barely a 100 men left, Baku Koshin tells them they will break through the enemy’s central infantry formation and assault the summit of the hill to slay the Wei General Kyuu Gen.
When they begin the charge Kyou Ji tells him he’s about to puke and he tells him to puke as he runs, because the moment they stop its the end for them. Not to mention the cavalry is leaving them behind. Then the cavalry’s numbers start to dwindle, Kyou Ji is then stabbed in the back.
When they break through the Wei, and are right under the hill they have close to 40 men left. Then Taku Unit arrives, with Kyou Ji being carried by Bi Hei and Bi Tou, which makes 46. With their strength almost gone Baku Koshin tells them that he wont cut them slack and anyone who does not reach the summit he will cut done afterwards. But those who do will be bestowed the honour of being the greatest contributors to this battle. And be rewarded appropriately, with a reward ten times higher than normal.
When they make it to the summit they are able to hold their ground thanks to general Ou Ki intervening into the battle. Then Shin goes done to join the battle with Duke Hyou. After Duke Hyou kills Go Kei the Wei retreat. Bi Hei begins to cry over all the men they lost, and how they managed to survive. And instead of taking Keiyou City, Duke Hyou has them return home.
Later, Hai Rou explains to Shin that soldiers cut off enemy soldier’s heads for a bounty. And given their accomplishments, they don’t need to bother with that, and besides they’re probably to late anyway.
On the march to Bayou the new unit started gathering up. Kou mentioned saying Shin hasn’t showed up yet. Hai Rou thought Shin was with them, and has already checked the other places out.
When they begin forming squads, the unit starts to worry. But Den Yuu spots him. When he arrives he say to him and Denyuu that it doesn’t matter if they get all the rough types just make him some strong squads.
He then informs everyone that this unit will be a special 100-man unit. That does belong to any division, and answers directly to general Ou Ki. And they will be sent into the most important clashes, and undertake the hardest fights. In exchange the rewards will be huge.
As Shin begins to introduce their his lieutenant En, everyone wonders who the second is?
That night Kyou Kai arrives, to everyones amazement to be their lieutenant.
As Shin begins to introduce their his lieutenant En, everyone wonders who the second is? Except for his old squad members.
That night Kyou Kai arrives, to everyones amazement to be their lieutenant.
When they reach Bayou instead of charging the city they advance right. To avoid fighting on the open field with Zhao cavalry. Instead of charging with the left army, they are assigned by General Ouki personally to flank the Zhao forces while they are engaged in combat with the Qin Left Army and take General Fuu Ki’s head in the midst of the confusion. Ouki then bestows them the unit the name of the Hi Shin Unit. They proceed by moving behind the thicket, to loop around the Zhao, to strike them where they least expect.
Then while fighting Fuuki’s elite guard unit, Shin splits the unit in half taking the squads that can still run, fight, and still have energy in them. When Kyo Gai says its 30 vs 300. He tells them not to worry, it might be 300 but there’s only 150 of them between them and Fuuki. 15 deep and 10 across, which makes 150 men. All they need to do is cut down ten ranks of soldiers and they’ll be able to reach the general. Later, Bi Hei tells him that they are already past ten ranks of soldiers. He tells him it’s not like the Zhao have been standing around, and their numbers have increased too. Then Kyo Gai asked him how much further it was. He tells him right in front of them is the general’s flag. When they manage to break through Fuuki discides to pull back his forces to create distance. Then Fuuki sends out his a cavalry unit to destroy them. Bi Hei tells Shin and Kyou Kai to run, since they were mounted they could get away. But he refuses to leave his men. But they are saved by the Qin Left Army. Then, Bi Tou tells Shin to go and take Fuuki’s head. But Den Ei tells them not to let Shin pull ahead, because after coming this far he’ll be the one who gets the general’s head. Shin tells him not to worry. Because his had will be the one to take Fuuki’s head but he’ll split the reward 100 ways, for everyone there, the one’s behind, and the ones who died. When Fuuki splits his forces and heads for the bushes Hai Rou notices that they’ll lose him for good. But before he can make it Qin flags come from the bushes. Giving Shin the opportunity to slay Fuuki.
When they head back to find the rest of their unit, they find no one left. Then Kyou Kai spots them. That night when Shin is upset about the death of 17 of his men Hai Rou tells him that those guys would be happier if he sends them off with a smile. Then general Ouki comes out of nowhere and agrees with him.
A few days later, the Hi Shin Unit was folded into the 4th army to hit the Zhao HQ with their whole army. They then charged the foot of the mountain to set up their HQ. Then they see that the Zhao had practically made it into a fortress. When they enter the Zhao start retreating. Den Ei notices that the Zhao were already long gone by the time they got there. And have moved their HQ and soldiers to a new location. That night they camp in the mountains with the with the rest of the Army. They are then informed that the Zhao have attacked. When they are formed into ranks, a giant man jumps from a hill, and starts slaughtering the unit. Shin then begins to duel him, then Kyou Kai intervings. He then tells them his name is Houken, the Zhao Army’s Commander-in-Chief. Shin and Kyou Kai pincer Hou Ken. Shin is quickly blown away by Houken. Then he fights Kyou Kai, and they have a fierce duel. Then 500 Zhao arrive under the command of Man Goku. Shin then rises and orders his to fall back and regroup, while Shin and Kyou Kai cover them. Instead the Kan Ou Army shows up and attacks the Zhao. During the chaos, Denyuu tells Shin that things have really turned into a mess. Also, that all their men have gotten split up. And they won’t get anything done by staying there, and decide on whether to join the attack or pull back. Hai Rou tells them not to move just yet. And even if this becomes a giant melee, their men still now where Shin is. And as long as they stay there everyone will slowly find their way back to them. When Shin wants them to fight Houken, Suu Gen tells him that he understands his feelings, but he should take a minute to calm down and think it through. And they cannot defeat him by blindly charging like that. If they were to fail in their gambit after entering the middle of that, there’s no doubt their unit will be annihilated. Shin reminds him of when they took Fuuki’s head, and how many of their men gave up their lives so they could take it. And how their centre and right armies sacrificed thousands, and what they had to show for it. That is what war is. But right now, the Zhao Commander-in-Chief was right in front of them. But he agrees with him, so he asks if anyone wants to pull out. Shin has everyone apart from him and Seki’s squad split into three groups. Take position surrounding Houken from three directions. Gathering as many of the nearby spears as possible. Then hold position and wait for the signal. On Seki’s whistle signal, all three groups made a beeline for Houken. Then threw spears at him from all three directions. He deflected all of them, but while he deflected them Shin snuck up on him from behind. He still noticed him, but Shin knew he would and dodged the swing.When he goes to cut him, Shin knew that Houken would still notice and go for another swing so he dodged it and slashed him. But it didn’t work. Before he could make another move he is hit by the backend of his glaive. And before Houken can kill Shin, Kyou Kai protects him, and is blow away. Then as he goes to kill Shin, he is protected by the Bi brothers and Taku. Then the unit comes to their aid. Then they retreat. They are then chased down by Man Goku. While on the run, a soldier starts wondering how things ended up as they did? Den Ei tells him to stop bitching, and its because they couldn’t kill Houken. Hai Rou tells him things would have been crazy if they succeeded, they would have hero’s of their village to heroes of the state. Den Ei starts laughing and agrees with him. He then says that Shin keeps getting more and more incredible. He tells Bi Tou to hang on to him no matter what, because it doesn’t matter how many of them die, so long as he stays alive the Hi Shin Unit will never die. Then they are attacked by Mangoku. The Bi brothers manage to get Shin out. Hai Rou goes to Mangoku to buy Shin time, and says to him if he really think that a half assed blockade is enough? And they are the Hi Shin Unit that blew right through the Fuu Ki Army of 20,000 before taking his head, and if he underestimates them they’ll take his head. Mangoku tells him to try it. Hai Rou then tells him that the Hi Shin Unit won't die there. They then retreat.
The next morning they find the others after hearing Seki’s whistle. Bi Hei tells everyone Shin will be fine in Tou’s hands. He tells them to send out search teams, and he has a pretty good idea what direction they’re in. But Seki tells them Shin has returned, carrying a Bi Tou. As everyone is relieved of their return, Shin tells Hei he’s sorry. And lays a lifeless Bi Tou down.
Now having lost contact with the other Qin forces, reduced to 13 squad leaders and 36 men the Hi Shin Unit began to revive. They picked up their weapons and began to advance forward without binding their wounds. They find a Qn flag, but it turns out to be a trap set by the Zhao general Shou Mou. They are saved by the Qin cavalry lead by general Ouki. After a fierce skirmish Ouki slays Shoumou in one swing.
They then travelled with the Ouki Army, when the cavalry and footsoldiers separated due to the mountainous terrain. Shousa asks Shin if it’s okay for them to rush forward in such a vulnerable state. On the off chance the Zhao have posted soldiers to ambush them, they’d get crushed. And he knows the general’s in a rush, but it’s a bit risky. Hai Rou thinks general Ouki knows that there aren’t any enemies there. Shou Sa asks how could he tell? Hai Rou tells him he doesn’t know.
When they reach the Zhao HQ, they learn that Moubu is under attack by the Zhao, and go to help him. As they are about to fight the Zhao the Zhao Three Great Heavens’ flag goes up to everyone’s surprise. Shousa notes after their last member Ren Pa defected to Wei the previous year, he thought they had dissolved. So Hai Rou states that it must be a new member. Then, as the Qin’s morale is almost covered by the Zhao’s Ouki goes and raises the Qin’s. Houken tells them that the right army will be bait to lure out the Zhao, and he will be the attacker. After Ouki’s lieutenant Tou engages the enemy, and exterminates their archers, the infantry charges the Zhao. As the arrows are about to come, they turn left to target the Zhao base camp. Then, Ouki takes to the field and battles Houken. Shin then asks Kyou Kai who does she think is stronger Houken or Ouki? She tells him Houken, and gets angered comments from the unit. Hai Rou states that they’ve lost a lot of comrades to him. Kyo Gai says they have earned the right to see Houken s final moments. Shousa says that they are a special unit that answers directly to the general. And Den Ei says the only orders they were given by the general was to be “bait.”
Shin tells them the only thing that matters right now is general Ouki's fight with Houken.
As Ouki is about to finish off Houken, he stops, and everyone hears rumbling. They are then surrounded by a huge Zhao army with a Great Heavens flag. The 2000-3000 spectators collapsed in an instant. And the location devolved into a huge melee with cavalry and infantry alike. The Hi Shin Unit then starts blowing through the Zhao.
During Ouki's and Houken's duel, Shin notices Gi Ka going to shoot Ouki. As Ouki was about to kill Houken, he is hit by an arrow from Gika shoots an arrow catching Ouki off guard before Shin cuts him in two, and giving Houken the opportunity to stab his glaive into Ouki's chest. His soldiers then drop their weapons in defeat. Then Ouki rises, and tells his men to never give up even until death. Then to prove it to his men he swings his glaive at Houken, who easily catches it. Then Ouki starts pushing down cutting Houken's neck. He then explains what a general is. Houken then pulls out his glaive and goes to slay Ouki, but it's blocked by Tou. Shin then hops on Ouki's horse to hold him up. Tou says his unit will act as the distraction, and Ouki's bodyguard team and the Hi Shin Unit will escort Ouki to the left at full speed. Then Mou Bu and his soldiers use their last reserves to open up a route for them.
At Ouki's final moments, he tells Shin it is impossible for him to train him. And for a great general like him to personally teach him is too food for a bug like him to begin with. And matters like those he needs to learn by running between battlegrounds himself. And delve into and overcome strife and carnage together with his men. And bestows him his glaive before dying.
Half a month later, the Ou Ki Army, which had remained at the front lines out of caution, returned home.