Kazunari Kazemaru (風丸和成 Kazemaru Kazunari), better known as Seiji Kazemaru (風丸征次 Kazemaru Seiji) or the Dragon of Sawasaki (沢崎の龍 Sawasaki no Ryū) is a character in the Soul series of fighting games, making his first appearance in the series' fourth installment, Soulcalibur III, and has since returned to Soulcalibur IV and Soulcalibur V. He is the first protagonist of the Soulcalibur: Kinouishi Fanverse.
What lies in his soul is Curiosity. In Soulcalibur V's promotional material, he is known as The Remorseful Shinobi.
In Soulcalibur V, Seiji has an alternate character called "Shin Seiji".
Seiji was the only son of the former pirate Seibei Kazemaru. During his time as a pirate, Seibei raided a port city called Sawasaki, where his crew was dispatched by samurai under the local daimyo, a Sengoku veteran named Nobuhiro Takazaki. Upon capture, Seibei swore to end his life as a pirate, and to become a soldier under the Takazaki clan.
As his father and Lord Nobuhiro were close, Seiji became best friends with the lord's eldest son, Hirosuke, who was almost the same age. At his coming-of-age ceremony, he would take the adult name Kazunari.
Starting from when he was 12, Seiji's father would frequently take him to visit Raikyo (雷共 Léi Gòng, JPN: Raikyō), a Chinese pirate who served alongside Seibei in his pirate crew. Having stayed in Japan after their defeat, Raikyo agreed to teach Seiji in the way of Shaolin martial arts from China, including barehanded kenpo training and basic skills and forms with multiple weapons. Master Raikyo would give Seiji a Wo Dao as a gift; a Chinese sword built in the Japanese style. The sword itself was known as Byakko (白虎), after the White Tiger constellation.
When Seiji was 18, he defeated Lord Yasuda, a rival daimyo to the Takazaki clan. His father Seibei was known to have died in this battle.
A year later, the Takazaki clan was taken over by Hideyoshi Toyotomi's forces. This loss motivated Seiji to set out on a personal training pilgrimage. Though he would not limit himself to Japan; he would travel across East Asia to honor his father, who had traveled to the Asian mainland many times during his days of piracy, particularly Korea and China. Starting in the northern parts of Korea, he traveled through the steppes of Manchuria and Mongolia, where he quickly learned survival tactics.
In China, Seiji came across a martial arts school in a small village. He challenged them with his own Shaolin style, only to be defeated by one of the students. Despite initial backlash against the seemingly cocky foreigner, the old master who ran the school, Tong Wufan, insisted on training him, curious as to how a Japanese samurai would know Chinese techniques.
Over the course of one year, Seiji improved his skills in Chinese hand to hand combat and weaponry, and eventually gained the respect of his classmates, who would see him as one of their own. Though he performed well with all weapons in the curriculum, he favored and excelled in the use of the dao, or Chinese saber, due to his previous training with Master Raikyo.
He also developed a close relationship with Master Tong's daughter, who was also his favorite training partner. In their off time, Seiji would often share his own war stories with the other students. Some claimed that he just did it to impress Lingmei. Others just saw his desire to entertain people. While he initially had feelings for Lingmei, they eventually faded by the time he returned to Japan.
Before returning to Japan, he also traveled further across China into Southeast Asia. It is said that he briefly spent some time as a mercenary for the King of Ayutthaya.
At the end of the year 1588, Seiji returned to the Takazaki clan a more mature and experienced man, ready to serve his lord once again.
The following year, a powerful oni called Dojishinsai (怒地震災 "Rage Earthquake Calamity") attacked Sawasaki. Wanting to test his skill, Seiji stepped up and was the only warrior to challenge the monster. Upon defeating and sealing Dojishinsai, Seiji became known as a "the Dragon of Sawasaki", and became local legend. Though Seiji was the one who subdued the demon and brought it to his mercy, Dojishinsai was sealed by the kunoichi Tsubaki.
In celebration of his feats, Seiji was arranged to marry a woman named Rinko Fujita, the daughter of a Yasuda general who defected to Takazaki after Yasuda's defeat. It was said that the two were initially opposed to it, but over the first year of their marriage, fell in love. The two were relatively close in age, with Seiji being only three years older.
The year is 1590. Nobuhiro Takazaki dies of illness.
Hirosuke, the new heir to the Takazaki clan, wanted to break free from Hideyoshi and restore his clan's former glory. He came up with a plan: To use the legendary sword, Soul Edge, which Hideyoshi seemed to have his eyes on, against him. He gave Seiji, his best friend since childhood, the mission of gathering information on Soul Edge, hopefully to gain the upper hand on other clans, and possibly become independent again. He knew that Seiji was a fine warrior, and trusted him above all others. On top of that, Hirosuke was also aware of Soul Edge's supernatural nature, and chose Seiji for the mission due to his experience with slaying a yokai the previous year, and for his experience with traveling the mainland. Immediately jumping on a chance to see the rest of the world, he agreed. Meanwhile, Lord Takazaki would continue to feign loyalty to Hideyoshi until the sword was out of Hideyoshi's grasp.
In order to keep a light load during his travels while staying protected, Seiji wore only a footsoldier's suit of armor, and carried nothing but his dao. He would then leave, saying his final goodbyes to his beloved wife Rinko. Little did he know, they would be expecting a child upon his return.
Seiji paid a visit to Master Tong's school, where he was met with a warm welcome. Wanting to make a name for herself rather than live in her father's shadow, Lingmei, also missing her friend, offered to join him on his journey. Though her father was initially hesitant, he ultimately felt that it would benefit her more. While Master Tong continued to train his students, Lingmei packed her favorite sword and left with the young samurai.
On their travels, Seiji and Lingmei met a Chinese warrior monk named Ji Gang, who tested them in combat. The duo were very close to victory, until the monk turned the tides and defeated them, even breaking Seiji's prized Byakko. He asked the young samurai why he was searching for Soul Edge, and he simply replied "because my lord asked it of me". The monk then warned him of its true evil power, and of the Azure Knight Nightmare, telling of the effects it has had on the world. Seiji made a new goal to gather information on its opposite sword, Soul Calibur, or as this monk called it, Krita-Yuga. For a short period of time, the monk even agreed to train the two, expanding the samurai's knowledge of Chinese combat forms, and refining the vigilante's skills. He also gave Seiji a new sword: a dao called Red Storm, which was said to have been forged by a swordsmith in Korea. Seiji renamed it Shin-Byakko (新白虎).
In addition, Ji Gang handed the two a fragment of Soul Edge, hoping that they could use it to find the sword and destroy it.
Seiji and Lingmei would continue to fight malfested in Astral Chaos, until Siegfriend Schtauffen defeated Nightmare, and the whereabouts of Soul Calibur seemingly disappeared. Shortly after recovering from the battle, Lingmei returned to China.
In this time, Seiji was nursed back to health by Wolfkronian peasants. The samurai would spend almost a year continuing to wander the lands of Wolfkrone and the rest of Europe, challenging warriors of all weapons and combat styles, and even learning a few himself.
Seiji would make one last stop in China before returning to Japan. He would spend a few days with Lingmei at her newly-established martial arts school, and the two would catch up on what had happened since the defeat of Algol and Nightmare.
Finally, Seiji returned to his lord with all of the new information, of the sword's true nature as an evil spirit rather than a benevolent one, and informed his lord of the two swords' supposed disappearance. Clearly, the warrior that stood before Hirosuke was a much wiser man, and now sure that neither Hideyoshi nor anyone else could obtain the sword, he gave his friend new opportunities to rise within their clan. Due to Seiji's accomplishments, the Kazemaru family were tasked with investigating supernatural occurrences and eliminating supernatural threats to the Takazaki clan, including the Malfested.
Seiji also came home to find that Rinko had born their first son, Ryota. He also found that Ji Gang had Byakko reforged and sent back to his home.
Eventually, Hirosuke accepted the way things were, and no longer cared for overthrowing Hideyoshi; there were clearly much bigger threats beyond Japanese borders, and Hideyoshi was now the least of his problems. The Takazaki clan's military force, including Seiji himself, would participate in both invasions of Korea on Hideyoshi's behalf, despite some personal disagreements with it. It was said that Seiji crossed blades with a hot-blooded national hero of the country. However, the outcome is unknown, as both survived fully intact.
It is also known that like many Japanese samurai in Korea at the time, Seiji took up the pasttime of tiger hunting. It was said that during one such excursion, he subdued a tiger with only his bare hands, using his kenpo skills. Though he came out victorious, he claimed that he learned something from the tiger. His fighting style would also come to resemble Tiger Fist Kung Fu as a result, despite him having no formal training in that particular style.
Seiji would further prove himself as both a warrior and a gatherer of information during the first invasion. For this, Hirosuke personally hand picked him to undergo training in ninjutsu. Now a ninja, Seiji would use his new skills in battles such as the second invasion of Korea, and on the battlefield of Sekigahara. He would make use of the island of Sawajima as a training ground for future generations of ninja, and also commissioned the construction of a Buddhist temple on the island.
During the first invasion, Rinko would bear Seiji's twin children, a girl named Aoi and a boy named Kyuzo. Seiji would not see them until 1594, during his return to Japan until 1597.
During the second invasion, Seiji would also participate, though he would often also take mercenary jobs around the country, also fighting off northern invasions from the Manchurians, and helping innocent Korean commoners on the side. In late 1598, he would also help with relief efforts in villages damaged by the war.
17 years ago, Seiji Kazemaru benefitted the Takazaki clan with information on the Soul Swords. 11 years ago, he was promoted, and bestowed with the status of a ninja. Within these 17 years, Seiji would also take jobs guarding merchant ships to Southeast Asia, gaining more opportunities to explore the world.
In 1600, the Battle of Sekigahara would occur. The Takazaki clan would fight for Mitsunari Ishida's Western Army. While Seiji initially objected, he would accept this, seeing it as an opportunity to see Hideyori Toyotomi, Hideyoshi's son, down a different path from his father.
After the end of the battle, Hirosuke Takazaki submitted to the Tokugawa clan and became their ally as a tozama daimyo. However, he would eventually succumb to wounds from Sekigahara.
For the death of his friend, Seiji Kazemaru blamed himself for not being able to prevent it. However, before Hirosuke's death, his final dying wish was for Seiji not to commit seppuku, but to continue to serve the clan. Hirosuke's young son, Hirotsugu Takazaki, took over, though he was still a child. Young Hirotsugu would spend the next few years under the tutelage of his advisors, some of whom took advantage of their positions in the most corrupt ways.
Ever since Sekigahara, Seiji lived what appeared to be a lavish lifestyle due to his accomplishments as a general of the House of Takazaki. Since then, he would often spent most of his time at taverns and geisha houses, even taking concubines despite a history of strong loyalty to his wife, Rinko.
However, none of this would truly satisfy him. Seiji felt that he could never find peace, both due to the atrocities he was forced to commit in Korea, and due to the death of his best friend and master. All of it was merely a distraction.
The year was 1607. Seiji heard news of the return of the Soul Swords. After notifying his lord Hirotsugu of the potential rise of threats beyond their borders, the experienced general was tasked with neutralizing them. For the following months, he resumed his training, even cutting down his own sake intake to stay focused. However, due to his important position in the clan, he appointed a kagemusha in his place. The only ones who were aware of the switch were Lord Hirotsugu and Seiji's own family.
A few mere days after Lord Hirotsugu was notified, a mysterious merchant sold what he claimed to be a fragment of Soul Edge to Seiji, which he took to use as a way to find the whole sword. Seiji took the fragment home for safekeeping until he would leave for his journey.
One night, Rinko fell deathly ill. The fragment caused an incurable illness in her, which nobody was aware of. Though Sawasaki's finest doctors could do nothing, it was said that Seiji consoled and comforted his beloved in her final moments. Though he continued to spend time with concubines and at geisha houses in the final days before his departure, it was said that nothing could ease the pain of losing Rinko. Eventually, the disease even spread to his concubines, even causing some of them to become malfested rather than diseased. A few were able to hide it well, though one went berserk, forcing Seiji to put her down with lethal force.
After a week of mourning, the veteran ninja set out west, leaving his children behind. Before leaving, he passed his beloved dao Shin-Byakko to his son Ryota, instead taking only his specialized ninja weaponry with him. Ryota was now the successor of the Kazemaru clan. Should Seiji not return, the young 17-year-old boy would succeed him in family and political matters.
Seiji's new goal in addition to serving Lord Hirotsugu was revenge against Soul Edge. However, Seiji also had another secret goal: seeking an honorable death, both to finally end the pain of losing his lord and his wife, and to avenge those that he had wronged in Korea.
Seiji traveled through China, where he stopped by the swordsmanship school of his old friend and traveling companion, Tong Lingmei, now married to Wu Chun. Though she refused to follow him due to wanting to manage her school, she allowed him to stay and train with her for the time being. During this time, Seiji also learned to wield a new weapon recently discovered by the Wu family: the nunchaku. The Wu family was also hosting a Ryukyuan warrior, who had previously met Wu Chun while he was on a diplomatic mission to Ryukyu, and introduced them to the new weapon.
Ryuki asked Seiji if he could travel with him. Though the ninja initially refused, he eventually allowed it.
While traveling through Western China, the duo encountered a young thief. After Seiji defeated her in a duel of deception and pragmatism, she joined them on their quest.
By the time the three reached Europe, they were caught in the war between Schwarzwind and the Malfested. Though they did not necessarily take a side, Seiji used his information gathering skills and sold information to Schwarzwind officers, so that they would give him leads on the swords. In the meantime, Ryuki and Jiaohu would take mercenary missions to make money for their travels.
The trio eventually found leads on the swords, and fought alongside the warriors of Schwarzwind.
Towards the end of the war with the Malfested, the trio encountered two Astaroth. One destroyed Seiji's twin kodachi, and the other threw Ryuki off a cliff, apparently killing him. Seiji and Jiaohu killed the two Astaroth in revenge. Now without a weapon, Seiji kept the young warrior's nunchaku in his memory, which was all that seemed to be left of him.
After reuniting with the Schwarzwind forces, Seiji and Jiaohu participated in the final assault on Ostrheinsburg.
When the war ended, the swords disappeared from the sight of all common people. Seiji stayed in Europe for approximately a year, assisting various bands of warriors in taking down malfested remnants. During this time, he would truly rediscover what it meant to be an adventurer, eventually accepting everything that had happened to him.
Later Life and Legacy
The last known battle that Seiji participated in was the Siege of Osaka, alongside his children, most of who were now of age. Though the Takazaki were a tozama clan, they fought alongside Tokugawa against the last of the Toyotomi clan, in the hopes of gaining favor with the shogun despite their status. It is said that Seiji felt nothing but joy at fighting alongside his children against the clan who forced him to fight in Korea. Though he had already accepted what he had done, it was at this battle that he finally found true peace. However, most historical records claim that he was killed in this battle. Ryota Kazemaru's memoirs claim that Seiji was among the men who killed the legendary warrior Sanada Yukimura.
Within the former lands of the Takazaki clan, the Kazemaru family would remain prominent well after the disappearance of the Soul Swords, due to Seiji's status as a local hero. Thanks to his heroic deeds, the family was tasked with investigating and intercepting outside threats to the Takazaki clan before they reach their borders. While virtually unheard of throughout the rest of Japan, the Kazemaru family is still remembered as heroes by the locals to the present day. Shin-Byakko has become a de facto symbol of the head of the family's main branch. A handful of Seiji's present day descendants still own and run businesses in Sawasaki, while others have moved abroad to places such as the United States, Brazil, and others. It is said that a statue of Seiji Kazemaru is prominently displayed in Sawasaki's largest park, depicting him wearing full Japanese armor, and standing heroically with a Chinese war sword in his hand.
It is unknown what happened to Seiji's original sword, Byakko. A monk in a local temple in Sawasaki claims that Seiji had sealed his own soul inside it upon his death bed by using an onmyodo spell on himself, and that he is of a single line of people to whom that story was passed down. However, others, especially historians, claim that this is simply a story he tells to entertain children and impressionable tourists.
Seiji is an open-minded traveler with a love for exploring who, while able to show respect for traditions, accepts changes and advancements rather than shunning them. Much of this is a result of his training pilgrimage across East Asia. However, it has also made him more easily susceptible to his own emotions. In spite of this, he will still carry out his duties as a samurai.
In Soulcalibur V, Seiji is much more weary of the world. Having been forced to commit great atrocities while in Korea on behalf of Hideyoshi Toyotomi, and having lost his daimyo and wife, it has made him much more cynical and weary, wishing to find a worthy opponent to finally finish him honorably.
He would not find peace until the Siege of Osaka in 1615, where he and his children join in vanquishing the Toyotomi clan.
Seiji is a young Japanese man of average build and slightly tanned skin. His long black hair is usually tied in a ponytail.
In Soulcalibur III and Soulcalibur IV, his primary outfit consists of a dull crimson suit of Japanese armor sans helmet, over a blue kimono and hakama, and black tabi. In Soulcalibur IV, his secondary outfit is a black kimono with a blue hakama and straw sandals over black tabi. IV also features a bonus third costume, which is entirely Chinese, in contrast to his usual Japanese outfits. It consists of a a wide straw hat, a blue changshan, a wide green sash, black pants, and black cloth shoes with white socks.
In Soulcalibur V, Seiji's age shows, as his ponytail is much longer while he sports a beard. His primary costume is a dark red shinobi shozoku with silver armor on the shins and forearms. His secondary costume is lifted from IV, a black kimono with a blue hakama, but with an added red haori. He has a bonus third costume which is a black and red Chinese garb with a black ninja mask.
In Soulcalibur V, he has an alternate costume as Shin Seiji. It resembles his default ninja outfit, but in the P3 colors, without the hood or the arm guards, instead with bandages around the forearms. Shin Seiji also possesses an alternate color resembling his P3 outfit from Soulcalibur IV.
In Soulcalibur III, Seiji uses a fighting style identical to Arthur's "Katana" moveset. Though he can use any weapon of the moveset, his preferred weapon is the Wo Dao, representing his personal sword Byakko.
In Soulcalibur IV, Seiji's fighting style resembles Yun-Seong's, and the White Storm represents Seiji's own sword, Shin-Byakko. The two swords are near-identical with only subtle differences in markings, and it is implied that the two swords may have been created by the same blacksmith.
In Soulcalibur V, due to his new status as a ninja, Seiji uses two kodachi in a style reminiscent of Taki or Natsu. As Shin Seiji, he uses a nunchaku style identical to Maxi, having learned Ryukyuan martial arts from both Lingmei and Ryuki.
Appearances in Other Media
Though he originated in the Soulcalibur series and is ultimately tied to it, Seiji Kazemaru has appeared in countless other video games. His appearance in the Saints Row series have caused the existence of an alternate version of him who exists elsewhere in another universe.
Seiji appears in Mortal Kombat: Armageddon as a playable character, in a cross promotion between the Mortal Kombat and Soulcalibur franchises. This is his first chronological guest appearance. He is heavily based on his Soulcalibur III incarnation, wearing his usual crimson armor, though redesigned in a style that better fits the typical Mortal Kombat aesthetic. He uses "Tong quan" (Fist of the Tong Family) as his unarmed fighting style, and a Chinese Broadsword as his weapon style. While in this realm, he fuses with a wandering spirit, granting him magical powers on par with the kombatants around him.
He is said to have been brought to Edenia by Soul Edge after it sensed the energy and concentrated fighting spirit emanating from the Mortal Kombat universe. While there, a wandering spirit fused itself to him, granting him magical powers and an enhanced connection to other spiritual beings.
His personal story involves him returning to his own time after reaching the top of the pyramid, though separating himself with the spirit in the process, thus losing his magical abilities. He narrowly escapes Armageddon, returning to Soulcalibur's Earthrealm in his native time. As he returned, the spirit used its magic to make sure that Seiji would only remember the events of Mortal Kombat and Armageddon as a dream, so that he would continue his own quest unhindered.
A clone of Seiji Kazemaru exists in the Tekken series as a fan character. His descendant, Gaku Kazemaru, is also the protagonist of Kinouishi's Tekken arc.
Koei Warriors series
For unknown reasons, Seiji Kazemaru has close ties to Koei-Tecmo's Warriors/Musou (無双 Musou) series.
Though he is not available as a playable character, a story containing Seiji exists in the Warriors Orochi universe. Much like Sophitia, Seiji is wandering Europe after the events of Soulcalibur IV, only to find himself taken by a rip in time to a time-displaced realm. After many adventures and battles against Orochi, he is ultimately returned to his own time, wiped of all memories of Orochi's dimensional realm.
Due to the Orochi world's nature of having multiple timelines, one of the less fortunate timelines has Seiji discover the secret of the connections between time periods and dimensions, and incidentally end up in the Dynasty Warriors timeline. This results in the existence of two Seijis; one who returned to his own world and time period with no memories of the events of the Orochi War, and another who exists in an alternate Dynasty Warriors timeline.
In Koei's games, Seiji makes his playable debut in Samurai Warriors 3, where he uses a generic katana moveset. He returns in Samurai Warriors 4, again using the same moveset. He is typically an offense-oriented character with a focus on combos.
Seiji appears again as a playable officer in Dynasty Warriors 8: Empires, where his moveset is altered to more closely resemble his combat style in Soulcalibur IV. He uses the same weapon as Sima Zhao, while sharing Musou attacks with Guan Suo to reflect his Chinese kenpo training. This is later confirmed to be the alternate Seiji created by the multiple timelines of the Warriors Orochi events.
Saints Row series
Seiji is also a possible protagonist for the Saints Row series, with a very complex backstory. This version of him is actually a copy created by the complications of time travel. In this universe, he becomes a psychopathic gang leader, the President of the United States, and later the Emperor of the Saints Empire.
See Seiji Kazemaru on the Saints Row Fan Fiction wiki.
- Seiji's overall concept was inspired by fighting game characters who, like himself, are of Japanese origin and nationality, but use Chinese martial arts. These include but are not limited to Akira Yuki from Virtua Fighter, Hotaru Futaba from Garou: Mark of the Wolves, and Kokoro from Dead or Alive.
- Seiji's preference for Chinese martial arts despite being a Japanese samurai is also inspired by Ukon from Samurai Champloo.
- Seiji is inspired by Samanosuke Akechi of the Onimusha series, and Samurai Jack. Samanosuke's backstory involves him traveling across East Asia four years prior to the events of Onimusha: Warlords. The eponymous protagonist of Samurai Jack is also established as having traveled the world to learn different fighting skills, with much of his fighting style drawing from both Japanese swordsmanship and Chinese Shaolin kung fu. Seiji's backstory takes the premise of Samanosuke's backstory, while adding the martial training aspect of Samurai Jack's story.
- An integral idea for Seiji's backstory circa Soulcalibur V was a more historically accurate portrayal of a ninja. Though the franchise contains ninja in the form of the mystical assassins they are often portrayed as, Seiji became a ninja in the way a real ninja would have. Instead of being trained in mystical assassination arts from birth, Seiji was hand-picked by his lord for his accomplishments, and his skill in ninjutsu is focused more on information gathering rather than assassination, though he has been known to do both. Like a historical ninja, Seiji still keeps his same status and responsibilities as a samurai.
- In an example of hair color dissonance, the Soulcalibur series and other games depict Seiji's hair with a dark green shade, or as black with green highlights, even though his hair is officially black. This is a reference to characters such as Spike Spiegel or Bright Noa, who both have black hair, though their respective anime depict it as green.
- However, in anime-esque settings where unnatural hair colors are the norm, his hair is usually blatantly depicted as green.
- Seiji's 3P costume in Soulcalibur V is based on early Western portrayals of ninja. These designs, which are still commonly seen in "samurai and ninja"-themed Halloween costumes, often haphazardly combine Chinese and Japanese elements, and come in silky red and black color schemes.
- Seiji's story of traveling outside of his homeland and returning with aspects of different cultures is similar to the story of the Unicorn Clan from Legend of the Five Rings. The Unicorn Clan were a clan of samurai who left Rokugan to explore the rest of the world, only to return completely changed. While they still served Rokugan as samurai, their culture is a hybrid of Japanese, Chinese, and Mongolian, and they have been changed to the point where their samurai prefer the scimitar to the katana. Similarly, Seiji is culturally a mix of Chinese and Japanese as a result of his travels across East Asia; while he still identifies as Japanese and as a samurai who serves his lord faithfully, his personal mindset is more in line with a Chinese youxia, and his favorite weapon is the Chinese saber.
- There exist multiple alternate versions of this character.
- The original, who lives out his normal life as depicted in this article.
- Another one created by a timeline split in the Warriors Orochi universe, who ends up in an alternate Dynasty Warriors universe.
- An alternate version who leads a gang and later an empire in an alternate universe, as a result of a temporal anomaly caused by an alien warlord.
- A clone who was created 400 years after the death of the original.
- As Soulcalibur VI is confirmed to take place during the events of Soulcalibur, there may be some expansion on Seiji's time in China.
- PutYaGunsOn likes to think that if Seiji were featured in Injustice 2, he would be a Premier Skin for Robin due to his use of sword-based martial arts, and the costume itself would resemble his Soulcalibur IV appearance. The Birdarangs would likely be replaced with traditional Japanese throwing weapons such as kunai or shuriken.
Seiji Kazemaru on Another Stage of History (Note: User "The Strongest Bad" is PutYaGunsOn under another name)