Live action TV
Description
Hideyuki Kagawa is a professor at Seimeiin University who becomes the user of the Alternative Zero system. His involvement with the Mirror World begins by chance when he wanders into university room 401 and discovers a notebook belonging to Shiro Kanzaki. Though Kanzaki quickly snatches the book away, Kagawa possesses a photographic memory and is able to retain everything he read. Upon learning the severe nature of Kanzaki's experiments and the existence of the Mirror World, Kagawa dedicates himself to duplicating Kanzaki's work with the goal of closing the Mirror World permanently.
As a character, Kagawa presents a calm, intelligent, and collected exterior. He rarely displays his emotions openly, maintaining a demeanor that some might interpret as cold-blooded or unfeeling. However, this reserve masks a strong sense of justice and a genuine commitment to protecting others. His guiding philosophy is that true heroism requires the courage to sacrifice one life to save many. This principle forms the core of his teachings and his approach to the conflict with Kanzaki.
Despite his seemingly unemotional personality, Kagawa is a married man with a young son named Yuuta, and he deeply loves his family. He shows a warm, affectionate side when interacting with his son, demonstrating that his stoic nature in professional matters does not reflect an absence of personal feeling. His wife Noriko and son Yuuta represent what he is fighting to protect, even as his mission forces him to make difficult choices regarding their safety.
Kagawa's primary motivation is to stop Shiro Kanzaki's Rider Battle and close the Mirror World, which he sees as an existential threat. He views Yui Kanzaki as being connected to the Mirror World and its monsters, leading him to conclude that eliminating her is necessary to end the danger. This puts him in opposition to the main Riders, particularly Shinji Kido, who seeks to protect Yui. Kagawa operates not out of malice or revenge, but from a calculated desire to save as many lives as possible, even if that requires morally difficult actions.
His role in the story is that of an antagonist who believes he is acting for the greater good. Rather than being a traditional villain, Kagawa represents a contrasting ideology to the series protagonists. He recruits his students, Satoru Tojo and Hajime Nakamura, as allies in his mission, providing them with Alternative decks he developed based on Kanzaki's research. Together, they form a small group dedicated to ending the Rider Battle by any means necessary.
The relationship between Kagawa and his student Satoru Tojo is central to his character arc and his ultimate fate. Kagawa serves as a mentor and understanding figure to Tojo, who looks up to him as an ideal hero. He tries to guide Tojo and even invites him to spend time with his family in an attempt to preserve the young man's humanity. However, Tojo gradually distorts his teacher's philosophy about sacrifice. While Kagawa believes in sacrificing one to save many as a necessary but regrettable choice, Tojo comes to interpret this as meaning a hero must actively sacrifice someone they love. This warped understanding leads Tojo to betray and kill Kagawa using a Final Vent attack, a death the teacher accepts as part of his own principles. The irony of his death mirrors that of the thirteen Riders he sought to oppose his own student killing him based on a twisted version of his own teachings.
In terms of abilities, Kagawa transforms into Alternative Zero using his own version of the Advent Deck and V-Buckle. Alternative Zero is the prototype model of the Alternative system, a mimicry of the thirteen true Riders created from Kanzaki's notes. The suit is nearly identical to the completed Alternative used by Hajime Nakamura, with minor differences in the color of the shoulder tubes and slight variations in height and weight. As a pseudo-Rider system, Alternative Zero possesses impressive physical capabilities including punching power of 15 tons, kicking power of 22.5 tons, a maximum jump height of 50 meters, and running speed of 100 meters in 4.5 seconds.
Alternative Zero's design incorporates cricket motifs, and he is contracted to a Mirror Monster named Psycorogue, which resembles a humanoid insect. While it is unclear if the contract functions identically to those of the thirteen Riders, Psycorogue follows Kagawa's commands reliably. The transformation system uses a Visor called the Slash Visor, mounted on the right forearm, which reads Advent Cards in a manner similar to the Rouzers from later series. The cards burn with black flame upon scanning.
Kagawa has access to several Advent Cards. Advent summons Psycorogue. Sword Vent conjures the Slash Dagger, a weapon derived from Psycorogue's forearms. Accele Vent increases the user's movement speed. Wheel Vent transforms Psycorogue into a motorcycle mode called the Psycoroader. Final Vent executes the Dead End finisher, where Psycorogue transforms into the Psycoroader before Kagawa rams into the opponent at high speed. Only Alternative Zero is known to have performed this finisher, as the completed Alternative unit was destroyed before it could do so.
Throughout his appearances, Kagawa proves to be a formidable fighter whose photographic memory allows him to anticipate and counter attacks he has witnessed before. Despite his strength, his death at Tojo's hands marks a turning point in the story. After his death, his research notes later fall into the hands of Shinji Kido, helping to reveal the truth about the Mirror World and Yui Kanzaki to the main cast.
An alternate retelling of the story presents a different version of events where Kagawa succeeds in mass-producing Alternatives. In this timeline, Yui Kanzaki borrows the Alternative Zero deck from Kagawa to confront Odin, leading to a different conclusion to the Rider War.
As a character, Kagawa presents a calm, intelligent, and collected exterior. He rarely displays his emotions openly, maintaining a demeanor that some might interpret as cold-blooded or unfeeling. However, this reserve masks a strong sense of justice and a genuine commitment to protecting others. His guiding philosophy is that true heroism requires the courage to sacrifice one life to save many. This principle forms the core of his teachings and his approach to the conflict with Kanzaki.
Despite his seemingly unemotional personality, Kagawa is a married man with a young son named Yuuta, and he deeply loves his family. He shows a warm, affectionate side when interacting with his son, demonstrating that his stoic nature in professional matters does not reflect an absence of personal feeling. His wife Noriko and son Yuuta represent what he is fighting to protect, even as his mission forces him to make difficult choices regarding their safety.
Kagawa's primary motivation is to stop Shiro Kanzaki's Rider Battle and close the Mirror World, which he sees as an existential threat. He views Yui Kanzaki as being connected to the Mirror World and its monsters, leading him to conclude that eliminating her is necessary to end the danger. This puts him in opposition to the main Riders, particularly Shinji Kido, who seeks to protect Yui. Kagawa operates not out of malice or revenge, but from a calculated desire to save as many lives as possible, even if that requires morally difficult actions.
His role in the story is that of an antagonist who believes he is acting for the greater good. Rather than being a traditional villain, Kagawa represents a contrasting ideology to the series protagonists. He recruits his students, Satoru Tojo and Hajime Nakamura, as allies in his mission, providing them with Alternative decks he developed based on Kanzaki's research. Together, they form a small group dedicated to ending the Rider Battle by any means necessary.
The relationship between Kagawa and his student Satoru Tojo is central to his character arc and his ultimate fate. Kagawa serves as a mentor and understanding figure to Tojo, who looks up to him as an ideal hero. He tries to guide Tojo and even invites him to spend time with his family in an attempt to preserve the young man's humanity. However, Tojo gradually distorts his teacher's philosophy about sacrifice. While Kagawa believes in sacrificing one to save many as a necessary but regrettable choice, Tojo comes to interpret this as meaning a hero must actively sacrifice someone they love. This warped understanding leads Tojo to betray and kill Kagawa using a Final Vent attack, a death the teacher accepts as part of his own principles. The irony of his death mirrors that of the thirteen Riders he sought to oppose his own student killing him based on a twisted version of his own teachings.
In terms of abilities, Kagawa transforms into Alternative Zero using his own version of the Advent Deck and V-Buckle. Alternative Zero is the prototype model of the Alternative system, a mimicry of the thirteen true Riders created from Kanzaki's notes. The suit is nearly identical to the completed Alternative used by Hajime Nakamura, with minor differences in the color of the shoulder tubes and slight variations in height and weight. As a pseudo-Rider system, Alternative Zero possesses impressive physical capabilities including punching power of 15 tons, kicking power of 22.5 tons, a maximum jump height of 50 meters, and running speed of 100 meters in 4.5 seconds.
Alternative Zero's design incorporates cricket motifs, and he is contracted to a Mirror Monster named Psycorogue, which resembles a humanoid insect. While it is unclear if the contract functions identically to those of the thirteen Riders, Psycorogue follows Kagawa's commands reliably. The transformation system uses a Visor called the Slash Visor, mounted on the right forearm, which reads Advent Cards in a manner similar to the Rouzers from later series. The cards burn with black flame upon scanning.
Kagawa has access to several Advent Cards. Advent summons Psycorogue. Sword Vent conjures the Slash Dagger, a weapon derived from Psycorogue's forearms. Accele Vent increases the user's movement speed. Wheel Vent transforms Psycorogue into a motorcycle mode called the Psycoroader. Final Vent executes the Dead End finisher, where Psycorogue transforms into the Psycoroader before Kagawa rams into the opponent at high speed. Only Alternative Zero is known to have performed this finisher, as the completed Alternative unit was destroyed before it could do so.
Throughout his appearances, Kagawa proves to be a formidable fighter whose photographic memory allows him to anticipate and counter attacks he has witnessed before. Despite his strength, his death at Tojo's hands marks a turning point in the story. After his death, his research notes later fall into the hands of Shinji Kido, helping to reveal the truth about the Mirror World and Yui Kanzaki to the main cast.
An alternate retelling of the story presents a different version of events where Kagawa succeeds in mass-producing Alternatives. In this timeline, Yui Kanzaki borrows the Alternative Zero deck from Kagawa to confront Odin, leading to a different conclusion to the Rider War.