However, across the story it is revealed he is the Sakurazukamori (桜塚護, lit. "Cherry Blossomburial mound guardian"), Japan's number one assassin who is targetting Subaru. The character returns in the apocalyptic manga X as a combatant in the battle of Armageddon Dragons of Earth and Subaru's rival.
Before events of Tokyo BabylonEdit
Seishiro becoming the Sakurazukamori by killing his mother who tells him he will also be killed by the person he loves.
Seishirō appears as a veterinarian working in Shinjuku, Tokyo. He is friends with the meets up with 16-year-old Subaru Sumeragi, Japan's most powerful onmyoji, after the latter'sshikigami causes an unlikely meeting between the two at Ikebukuro train station. Seishirō begins a year of courtship that will ultimately change both of their lives. Often he professes his love for the boy, with Subaru's eccentric twin sister Hokuto enthusiastically supporting the pairing, much to Subaru’s embarrassment. Seishirō also protects Subaru on several occasions, even sacrificing his right eye to protect Subaru from a knife-wielding attacker, and also refusing to let the police file charges against the woman who attacked him purely because he knows that Subaru would not want her to be prosectued.
He using his powers, Seishirō obscures his true identity and personal details. At one point, when he and Subaru are having their fortunes read, he gives incorrect information about his birthdate and place of birth to hide his true self. After a year passes and Subaru finally realises his love for Seishirō, he is devastated when Seishiro reveals he is the Sakurazukamori, Japan's top one assassin. When Subaru was very young, he witnessed Seishiro having just murdered a young girl. Seishiro used his powers to block the boy's memory, then told him about the cherry blossoms being pink due to a corpse being buried beneath the tree. Expecting the boy to be sickened or afraid, he was surprised when Subaru's eyes filled with tears, as the boy asked whether the person buried there would be hurt by that. Impressed with the kid's purity, Seishirō made a bet with him: Should Seishirō meet Subaru again, he would live with the boy for one year, and act and speak as if he loved Subaru more than any other person in the world. If the assassin could come to love him after living a year with him, or even regard him as different from objects most people treat like trash, he would spare Subaru's life, but otherwise he would kill him. But Seishiro declares that he feels nothing for Subaru after their year together. As a result, he almost kills the young onmyōji, but Subaru's grandmother intervenes to free him from the illusion, leaving herself crippled as a result.
Seishirō disappears from Subaru's life after this point; Hokuto, fearing that he will come after her brother, offers up her own life in his place. Seishirō accepts and stabs her through the heart; with her last breath, Hokuto casts a spell whose effects would subsequently be revealed in X.
After leaving Tokyo following the events of Tokyo Babylon, Seishirō returns to the city to assume his place as one of the Dragons of Earth, one of the warriors destined to fight against the Dragons of Heaven to eliminate mankind. He encounters Subaru and other Dragons of Heaven while destroying one of the city's barrier but their fight does not conclude. Though still unemotional, Seishirō makes an unlikely friend with Fuuma Monou, the most leader of the Dragon of Earth, who while taking one Subaru's eyes in combat tells him that only Seishirō can grant Subaru's true wish.
Seishirō encounters Subaru for one final fight in the Rainbow Bridge. After some time of fighting, Seishirō heads in for the finishing blow. Hokuto's final spell takes effect, leaving Subaru with his hand through Seishirō's chest, killing the Sakurazukamori instead. Hokuto's final wish was Subaru could not be killed the same way she was.
Seishirō knew this, effectively committing suicide as Fūma states Seishirō's wish was dying at Subaru's hands. After the battle, Fūma offers Subaru Seishirō's remaining intact eye, revealing that it was Seishirō's wish to erase Fūma's trace on Subaru, which Subaru accepts. This act completes this ritual and, after regaining his full sight, Subaru becomes the 14th Sakurazukamori and one of the Dragons of Earth.
Seishirō appears briefly in the movie version of X; he and Subaru destroy each other in magical combat early in the film.
In the live-action sequel to Clamp's manga, Seishirō Sakurazuka is portrayed by Shihodo Wataru. In the film, the Sakurazukamori assassinates a former enemy of the Sumeragi clan; however, his signature hand-through-the-chest style of killing is dropped in favor of magically strangling his victims.
In the crossover manga Tsubasa: Reservoir Chronicle, Seishiro appears as a young traveler who gained the power to travel between worlds from the witch Yūko Ichihara in exchange for his right eye. He searches for the vampire twins Kamui and Subaru, like his younger brother Fuuma, he is a treasure hunter. Although the reason for searching the vampire twins remains unknown, Kamui states that he will kill Seishirō if he finds them. Seishirō possesses one of Sakura's magical feathers which allows him to summon oni to fight for him as well as modify them into swords he can change their shape. An experienced fighter, Seishirō was also the one to teach the dimension traveler Syaoran Li his kicking techniques. Although he grows happy with his development, Seishirō does not doubt in trying to kill Syaoran in Oto Country when searching for clues about the vampires. When coming to Japan to get information about the vampires' location, Seishirō is challenged by the "other Syaoran" who wishes to obtain his feather. In the course of the battle Syaoran manages to claim the feather, although Fūma comments that was his main intention from the start. He later leaves Japan to continue his search and is seen in the epilogue alongside his brother and the vampires.
Creation and conceptionEdit
Subaru and his twin sister Hokuto, as well as Seishirō, were first conceived by series creator Nanase Ohkawa for a dōjinshi novel about an onmyōji who hunts elves, of which only the beginning exists. The characters were twice drawn for covers, and when South asked Clamp to create a new series for them, these characters were used. In the dōjinshi, Seishirō was also a veterinarian, but though he had a dark side, it was nowhere near as pronounced. Thus, he was the character who underwent the most change from this early conception to the creation of Tokyo Babylon. Nevertheless, Seishiro was easier to write than Subaru as Clamp was more used to writing dark characters.In the dōjinshi, Seishirō's shikigami was named Nandaro ("Just what is this?"), andClamp privately still refer to it by this name. Yasunori Kato: Subaru and Seishiro's respective designs pay homage to this character, the protagonist of the fantasy novel Teito Monogatari, widely credited with starting the "onmyoji boom" in Japan.
Subaru and Seishirō appear in X because their relationship parallels Kamui Shirou and Fuuma Monou. They serve as an example to Kamui and Fuma: One of Xs most important developments is the question what these two will do so they will not end up like Subaru and Seishirō.Ohkawa found Seishirō to be childish due how he only deals with what appeals to him in contrast to Fuma who Ohkawa finds adult-like.In the sixteenth volume of the series, the rivalry between the two ended with Seishirō's death much to the surprise of most readers. As they believed Seishirō would actually survive, Clamp made it clear that Seishirō permanently died and would not return in future chapters.
Seishirō has been well received by publications for manga and anime. Mania Entertainment writer Mike Dungan found Seishirō's role in Tokyo Babylon as comical, with his romantic intentions for Subaru being hard to find genuine.Despite initially finding Seishirō "cliche", the writers from Manga Bookshelf were interested by the the true meaning behind his actions to Subaru. They were surprised by Seishirō's betrayal to Subaru as it constrasted other stories in which an traitor would redeem himself but at the same time they questioned his motivations in the past.Zac Bertschy from Anime News Network referred to Seishirō as one of the most deep villains from X, pointing that he was already developed in Tokyo Babylon. His confrontation with Subaru in the TV series was praised mainly because how their character designs were updated from the ones from Tokyo Babylon. Mania Entertainment's Chris Beveridge agreed with Bertschy, calling the episode of their final battle one of the best ones from the series focused on how their backgrounds are shown and tragic elements portrayed.In the book Understanding Manga and Anime, writer Robin E. Brenner referred to Seishirō's and Subaru's relationship as one of the most explicit ones from X adding that the romantic feelings between these two male characters were uncommon in western stories. Brenner stated that Seishirō's unheard last words were meant to force readers to interpret them into their own ways, something characteristic in manga series.In the first character popularity poll from Tsubasa: Reservoir Chronicle, Seishirō was voted as the sixth most popular character from the series.