The Sū-shin are a team of warriors that serve as Woo Heishin’s bodyguards and villains from Rurouni Kenshin.
The Sū-shin went with Heishin to the island that Yukishiro Enishi was waiting at, where they met Gein, who was just leaving. When the puppet master tried to shake hands with Heishin, the Sū-shin quickly blocked his way and Heishin explained that they had orders to not let anyone near him. They went with him to the mansion where Enishi was and accompanied Heishin to his meetings with Enishi. Once Himura Kenshin and his allies arrived, Enishi told Heishin he was now head of their weapon’s dealing organization, before telling him to get lost or he and his soldiers would be destroyed. As Heishin headed for the beach, the Sū-shin asked him if he run with his tails between his legs. He said they had no choice since until then, Enishi would be equal in a fight against the Sū-shin. But now he was different and Enishi, with all of his powers released, would be invincible so they would leave. However Heishin told the Sū-shin meeting Enishi’s enemies was inevitable so they'd show Heishin’s gratitude by taking Enishi’s revenge into their own hands. Sū-shin went with Heishin to the beach and upon meeting Kenshin and his allies, he told his bodyguards they must have held themselves back but now they could unleash their violent fury. Shinomori Aoshi, Yahiko, Sanosuke, and Saito stepped forward to face the Sū-shin, but Heishin told them to step back and asked Kenshin to come forward. He said if the former Battosai died quickly, they’d all be spared the pain of total annihilation. However when their response angered Heishin, he sent in the Sū-shin, who leapt into the air, landing between Aoshi, Yahiko, Sanosuke, and Saito in a circle. Aoshi read the names tattooed on the Sū-shin’s foreheads and noted that they were named for the Four Gods of Japan. Heishin introduced them, saying they protected him from four sides, the same way that the Four Godly Beasts were said to protect the four sides of the royal castle. Heishin explained that the Sū-shin were quadruplets who mastered weapons that mimicked the Godly Beasts. He said they normally stayed at his side as the Four Stars, but they become the Four Gods, unleashing their true powers, at his command. Heishin ordered the Sū-shin to kill one each and the four drew their weapons, before attacking different opponents with Seiryū facing Saito, Suzaku taking on Aoshi, Byakko confronting Sanosuke, and Genbu fighting Yahiko. However each was defeated one by one by their opponents.
Seiryū (which means Azure Dragon) wields a guan dao called the Chenron Daito and has the ability to know how to deal with his opponent’s moves by seeing them only once. After facing each other, Saito noted that Seiryū seemed all right, unlike his master, but said trying to fight Gatotsu with range didn’t make him less of an idiot. Saito attacked with Gatotsu and Seiryū held up his arm to take the strike, prompting the former Shinsengumi if he planned to die without taking a step. Seiryū responded that with one glance, he knew Saito was no ordinary man and trying to beat him without knowing his finish could cost the Sū-shin warrrior his life. Seiryū went on to say sacrificing his arm to discover his moves was a cheap price if it meant winning. Saito asked him if he thought he could win with one arm and Seiryū explained he prided himself on his ability to determine his opponent’s moves. He went on to say there had never been an instance where he couldn’t determine a move at first sight. Saito said that was quite an accomplishment, but even if Seiryū could see it, it made no difference if he couldn’t dodge it. He used Gatotsu as he said if Seiryū couldn’t counter, he’d never win and the Sū-shin warrior said he knew all that. He dodged the attack, saying he knew the weak point of that move was Saito’s right arm. Seiryū said if he slid into the blind spot created by the former Shinsengumi’s right arm, his move was vanquished, as he did exactly that and slashed near Saito’s shoulder. He tried using Gatotsu again, but Seiryū slashed his side and the Sū-shin warrior asked the former Shinsengumi if he now understood his move was useless. Seiryū told Saito to give up or bring out his next move, though he’d just conquer it right away. The former Shinsengumi noted that Seiryū seemed to be having fun since his freakish smile was back (the fanged smile the Sū-shin gained when they changed from the Four Stars into the Four Gods). Seiryū changed his face back to that which he had as one of the four stars, apologizing since laughing in the midst of battle was beyond rude and he knew that. But his face changed back to his fanged grin, saying that happened naturally when one was faced with victory. Saito used his Gatotsu again, telling Seiryū by looking at justice before victory, a losing battle could be enjoyed. The Sū-shin warrior said he’d conquered that move already, but Saito grabbed him by the face and said he didn’t have time to listen to the ramblings of a fool who only enjoyed winning battles. He crushed Seiryū’s lower face and used Gatotsu on his right arm, shattering his Chenron Daito and bringing him down.
Suzaku (which means Vermilion Bird) wields a pair of short swords called the Chucha Soengimu and has the ability to mimic his opponent’s moves. After attacking Aoshi, the omnitsu blocked with his sheathed dual kodachi and Suzaku told him to draw, since he knew what they were. Aoshi drew his kodachi and used his Onmyo Kosa, but the Sū-shin warrior used the same move, countering it. Suzaku explained his ability to mimic moves and said in other words, Aoshi’s moves would be reflected back to him until he died. After the omnitsu tried using his Kaiten Kenbu Rokuren, Suzaku did the same and noted that it looked like that was his best move. He went on to say Aoshi’s expression didn’t change when he mimicked it and he assumed the omnitsu understood what that meant. Suzaku said firing back a move he’d never seen before was immutable proof he was slightly faster and he was superior by just enough. Suzaku went on to say that all forms of combat began by mimicking those who came before and he was proof that the mimicker can become greater than his predecessors. Suzaku declared that since his mimicry was better than the original, he had no enemies and resumed attacking Aoshi. He eventually knocked the omnitsu’s kodachi away and prepared to finish him, saying the expression fools like Aoshi had when they were killed by their own moves was so entertaining. As he moved in to to finish it, Suzaku asked the omnitsu what his last expression would be, but Aoshi delivered a powerful kick to his face. He said that he was impressed by the Sū-shin warrior’s ability to mimic, but no matter how well he mastered mimicry, its weakness was easily revealed when faced with original moves combined from different styles. Suzaku told Aoshi to shut up and said he only landed that blow because he let his guard down and swung his swords at him. However the omnitsu caught the blade, saying it was his own sword and he knew every swing, before snapping it. Aoshi said if Suzaku were truly from the shadows, he’d finish him off, but he was just a fool drowning himself in the pleasure of battle, before delivering a blow that knocked Suzaku off his feet.
Byakko (which means White Tiger) uses a set of spiked armbands called Pafu Chemkun that he can change into a form called tekki, where he can punch with the spikes. Byakko’s specialty is his ability to use a variety of powerful strikes from different forms in combat, which he chooses depending on which is most suitable. After Byakko started fighting Sanosuke, he overwhelmed him with his different forms of blows and asked him how he liked it. He explained that by using the form most suitable for striking certain locations, he could hunt down his prey efficiently, like the tiger, king of the jungle. Byakko declared that he didn’t play tricks like analyzing or mimicking his opponent’s moves, but Sanosuke punched him in the face. He said Byakko talked too much and his weak strikes were annoying, then told him to use knockout blows if he wanted to win. The Sū-shin warrior told Sanosuke not to get carried away after one hit and he overestimated himself. However Sanosuke replied he heard that a lot, but it didn’t bother him and when Byakko said it, it just disgusted him. Byakko responded by launching a barrage of blows and said he was the one disgusted, but was punched in the face once again by Sanosuke. He asked Byakko if he was still going to tell him that was luck and told the Sū-shin warrior he’d play with him one more time, but he should come at him with a big move. Byakko said fine if Sanosuke wanted to die so much and threw sand in his face, before changing the form of his armbands into their tekki form. He punched Sanosuke with one, bringing him to his knees and asked him if he would continue to bark. However Sanosuke interrupted, saying again that small moves wouldn’t work and used his Mastery of Two Layers to blast Byakko into the air. When he landed, Sanosuke said he couldn’t play with the Sū-shin warrior any more and they should end this, before punching Byakko one last time.
Genbu (which means Black Tortoise) wields a staff with large flail-like ends that he can detach into a six jointed mace called Yunmo Seikuan and his specialty is his strategies in battle. After Heishin expressed his outrage that three of the Sū-shin had been defeated, Genbu told him not to fret as he took on Yahiko, who’d used blade crossing to catch his staff, and said he’d fill the gap the others had left. Heishin said he was one to talk since he hadn’t been able to make one move against Yahiko. Genbu replied that the boy had been looking for a chance to make a big move, so he was actually not moving in order to observe. Yahiko tried using his blade-crossing attack, but Genbu detached his staff into links, smashing the boy into the ground. He explained what the weapon was and said Yahiko’s secret move was useless against it. The boy got back to his feet and Genbu said he had young eyes that knew no yielding, so it would be most enjoyable to quench them. As they went at each other, he said the younger the opponent, the more enjoyable it was to fight them, since it was so enjoyable to deprive them of their future. Genbu reconnected his staff and swung it on Yahiko, who used his blade halting technique to stop it. However the Sū-shin warrior detached it into its mace form again, which he used to flip the boy into the air. Genbu then reattached it into staff form again, smashing Yahiko onto it, then slammed him into the ground. Thinking the boy was finished, Genbu looked away, but Yahiko attacked him again and said he would fight worthy of Kamiya Kashin-Ryu’s first student, so he could greet Kaoru with victory. Yahkio told Genbu to come at him with his staff, to which he responded that his secret blade halting technique was useless. Yahiko just responded secrets were secret because they couldn’t be easily defeated and Genbu thought to himself that he couldn’t get confused by his taunts, he’d already beat Yahiko’s move twice, dealt him blows to the stomach and chest, and he was just a kid. Genbu said he would do as the boy wished, but this was the end and attacked, but Yahiko used his blade halting to press his shinai to the back of his staff. This left Genbu unable to detach his staff without backing up, which would leave him open to blade crossing and if he tried to force the boy down, Yahiko would use blade crossing. The boy said because of its bizarre construction, the staff had reduced durability and asked Genbu what he would do, since if he didn’t act soon, his weapon would be gone. When he couldn't think of what to do, Yahiko shattered the staff and struck him down.