|Kana Name||周瑜 公瑾|
|Romaji Name||Shūyu Kōkin|
|Date of Birth||February 23|
|Family|| Goei (Aunt)|
Hakufu Sonsaku (cousin)
|Seiyu|| Satoshi Hino (Japanese)|
Ted Sroka (Seasons 1, 3-4)
Ed Paul (Season 2) (English)
|Manga Debut||Chapter 1|
|Anime Debut||Episode 1|
Koukin Shuuyu is Hakufu's cousin, and her childhood friend. He vows to serve and protect her at all times even if it costs his own life. He also has a crush on Hakufu.
Koukin Shuuyu is Sonsaku's childhood friend and most loyal subordinate. When Sonsaku's father went to war, he left Sonsaku in the care of Shuuyu's father, and the two grew up like siblings.
Koukin is a frail person who has dark blue hair that reaches to the back of his neck and covers his forehead. He wears his highschool uniform, light brown vest a button up shirt and black pants, most of the time. He is also very cute and handsome and even Kanu develops an interest in him.
Despite being a good fighter, Koukin is very shy and prefers to stay out of fights. Although he is a C-rank, only his lack of confidence and his short resume of victories (or battles for that matter) keep him from becoming A-rank, despite already having the power of one.
Story (Manga) Edit
Introductory Arc Edit
Koukin is first accidentally walking in on Saji's making out session. Saji catches him and he apologizes, even though Saji doesn't mind. Saji then tells Koukin to be quiet as two boys run to a fight, stating that it was some very masculine female. Koukin runs toward the fight to find his cousin, fighting a B-ranked fighter named Gakushuu, who easily throws her into a wall, that unfortunately Koukin got in the way of. Koukin shares his lunch with Hakufu Sonsaku, his cousin, and after she eats Hakufu initially tries to fight Gakushuu again, having placed a latent technique that would relax his muscles in a few hours, although she was stopped by Koukin.
Koukin is then seen training at his own house, when his maid tells him that Hakufu had woken up. Koukin and Hakufu then eat lunch together, and Koukin explains what their magatamas are, which represents their rank, and how they can rank up by beating other fighters.
The Big four Arc Edit
Koukin, after barely being able to make it past the school gate, is greeted by the rest of the fighters of Nanyo, who plan to keep him from Hakufu, per the imperial order of their leader Enjutsu. Koukin is able to fight off all the fighters, and tries to go get Hakufu, but is instead greeted by Saji, who stops him from going through, being under strict orders, although Saji does offer Koukin a deal, that if he is able to beat him he may go to Hakufu.
Koukin then wakes up in a hospital, where Gakushuu is waiting for him, only remembering from his fight with Saji, a dozen punches, and a dozen kicks. He then asks what happened to Hakufu, and Gakushuu tells him what he knows, from that day.
Hakufu's Broken Spirit Arc Edit
Koukin is next seen trying to wake up Hakufu, but finds that she was no longer there, as she had snuck out, having had a broken spirit, after supposedly losing to Ryomou. Koukin is later seen at Nanyo, stating that he had searched all night for Hakufu. He then finds her knocked out at Nanyo Academy, after practicing.
Toutaku's Retaliation Arc Edit
Koukin and Hakufu are seen training a basic style, and although Hakufu had only started, Koukin is impressed at how far she has come along with the move. Koukin and Hakufu are later confronted by people from another school.
Story (Anime) Edit
Koukin is first seen helping an injured Hakufu, his cousin, to his house where they are met with his aunt Goei, who stated she will be staying with them. Koukin is then confronted by a bunch of Nanyo fighters, finding out that Enjutsu wants them dead, and is able to defeat most of them, except Saji who proves too much for him. Koukin then witnesses Hakufu's transformation into the dragon state, during her fight with Shimei Ryomou.
Koukin is next seen kidnapped by Yoshu academy fighters. However, he is able to break his restraints and begins to fight Shigi Taishiji, making him promise that if he is able to hit him, Taishiji will not harm Hakufu. Koukin is able to do that, but it proves useless as Hakufu still decides to fight Taishiji.
Koukin then participates in the great fighters tournament, although is not able to participate in any of the fights, as Koukin was injured during all of the fights, or was not able to participate as another team member was fighting in his place.
Koukin goes to Nanyo academy, receiving a message from Gakushuu. However, he is knocked out by a sneak attack from Kouha Kannei. He then wakes up in the boiler room chained along with Gakushuu, and finds Genpou Saji, who reveals his dastardly plan to them, stating he made Kannei crazy, and he was the one who was sending in orders, in place of the deceased Enjutsu.
Koukin and Gakushuu are then taken to a cliff, where they watch a possessed Hakufu, Ryomou, Saji and Ukitsu fight it out, ending with Hakufu, Ryomou, Gakushuu, and Koukin stopping Saji from killing himself.
Koukin then stops a possessed Hakufu from killing Ukitsu, during their fight, helping Hakufu gain temporary control of the dragon. Koukin then watches as Hakufu and Ukitsu throw their sacred beads away, stating they no longer wanted to follow destiny.
Koukin is first seen at his dad's house, with Hakufu, and Goei, enjoying themselves, when the newly acquired Kyosho fighters, sneak attack them. Koukin and Hakufu are able to take out multiple enemies, but it was Goei who eventually defeated them all. Kakouton then appears, making the Kyosho fighters leave, as it was his orders to kill Hakufu, not theirs, and Kakouton then talks with Koukin, Goei, and Hakufu. Kakouton explains the reason for the attack, was that one of Nanyo's fighters, Kannei, had killed his best friend Kakuka, and that there was nothing they could do to stop this fight.
Koukin is later seen with Gakushuu at Nanyo, where Kakouen sneak attacks the school. Koukin then watches as Gakushuu holds off the enemy, long enough for her to realize that Ryomou was no longer there.
Koukin is next seen at the place where the big four meet, reading the rock in the middle of the area. This revealed that Hakufu Sonsaku was the conqueror from the west, and that she could not be killed so easily by Sousou. Their meeting is then interrupted by Youjo who brings the bell of peace with her, not wanting to fight, but invite Nanyo to a meeting with Seito. Saji interrupts and tells everyone that Youjo was the one who actually killed Kakuka, and that it was constructed by Komei, but in the end Saji and Ryomou decide to go. Koukin was unhappy at this revelation as he did not want to have a relationship with Seito as he blames Komei for what happened to Hakufu.
Koukin then goes to Seito, where he meets Kan-u, who deduces that Koukin was not going to Komei for a friendly visit. She tells Koukin to turn back, or he will have to face her in a fight. When he refuses, Kan-u realizes that his anger was towards getting revenge for Hakufu. Instead of fighting, Kan-u asks him if Hakufu would want that. Koukin then realizes the error of his ways, and decides to go back and join Nanyo in the Battle of Red Cliffs.
Koukin, along with the other Nanyo and Seito fighters, then wait at the location of the battle, which will decide who will hold the Dragon Jade, and Kanto, for Kyosho, by having a picnic. Kyosho finally appears, and the fighters, of Nanyo and Seito split off into a one on one battle with one of the respective members of Kyosho, Koukin's opponent was Chuukou, and although Chuukou had the upperhand in strength, Koukin was able to out smart, using the line, combined with his chi, to cause an explosion causing debris to fall on Chuukou. Koukin then watches as Hakufu and Gentoku fight and defeat Sousou.
Koukin is seen with Saji trying to study for his exams, but is unsuccessful do to Saji's usual methods of "studying" constantly being interrupted by his female friends.
|Female Fighters||Shimei Ryomou • Hakugen Rikuson • Roshuku Shikei • Shiyu Shokatsukin|
|Male Fighters||Koukin Shuuyu • Gakushuu • Genpou Saji • Kouha Kannei • Enin • Tokubou Teifu|