Live action TV
Description
Before his death, Jun Maehara was a 20-year-old member of the Nozama Pest Control Service, also known as the extermination squad. He possessed a sharp mind and was responsible for strategic planning and hacking, often using his analytical skills to devise infiltration strategies for the team. His nickname among his comrades was "Ossan" or old man, a somewhat ironic label given his young age. He had a well-trained physique befitting a mercenary and a particular fondness for chess, a hobby that reflected his methodical and tactical thinking. As a person, he was kind and a valued member of his tight-knit group of Amazon hunters, which included leader Shido Makoto, Nozomi Takai, Mamoru, Kazuya Misaki, and Kouta Fukuda.
Jun’s fate took a tragic turn during an encounter with a former teammate, Ryusuke Otaki, who had lost control and transformed into a cannibalistic Dragonfly Amazon. In a moment of hesitation, Jun was attacked and fatally wounded by Ryusuke. Rather than expressing anger or despair, he accepted his death quietly, finding a small measure of solace in the fact that his life was ended by someone he once considered a comrade. His body was subsequently recovered in secret by Yugo Tachibana, a high-ranking official at Nozama Pharmaceutical.
Instead of being laid to rest, Jun’s corpse became the subject of a revived and unethical experiment previously shelved due to moral concerns: the transplant of a new, more potent strain of Amazon cells into a human cadaver. This process brought him back to a state of existence as a new type of being, classified as a Sigma-type Amazon, or the Fourth Type. He was reclassified as a product of Nozama Pharmaceutical's International Business Strategy Headquarters, a living biological weapon developed to surpass the older Amazon types. To complete his transformation, he was given a black replica of the Amazons Driver, a belt that copied the original’s function but added a crucial modification to block the sensation of pain.
As Kamen Rider Amazon Sigma, Jun’s personality underwent a complete and harrowing transformation. While he retained his memories of his past life and could still name his former colleagues, all emotional attachment and warmth were stripped away. The kind and strategic young man was replaced by an entity that operated with cold, machine-like efficiency. His love for chess twisted into a morbid game, where he would coldly announce how many moves it would take to defeat an opponent, treating living beings as mere pieces to be captured. He became devoid of empathy, capable of attacking his grieving friends without a flicker of hesitation, as seen when he callously threw Mamoru, who had rushed to embrace him believing he had survived surgery. He functioned as an unfeeling puppet, taking orders from Tachibana and the corporation without question, motivated solely by the directives programmed into his new existence.
Within the story, Jun, reborn as Amazon Sigma, serves as a tragic antagonist and a powerful physical threat to the two main Riders, Jin Takayama (Amazon Alpha) and Haruka Mizusawa (Amazon Omega). He was designed specifically to be superior to them, boasting greater physical statistics and the ability to ignore pain, which allowed him to continue fighting even after sustaining critical damage. In his first encounters, he overwhelmingly defeated both Alpha and Omega, nearly killing Haruka by piercing his torso. His role escalates the central conflict by demonstrating the corporation’s cruelty and willingness to sacrifice human lives for profit, turning a beloved former ally into a weapon.
Jun’s key relationships are defined by their tragic before-and-after nature. With the extermination squad, his revival transforms their grief into horror as they are forced to fight a ghost. Mamoru, in particular, shares a poignant moment, as his initial joy at seeing Jun alive is met with brutal violence. With his creators, namely Yugo Tachibana, he has no relationship—only a master-to-tool dynamic. Tachibana sees him as a successful commercial product, a "bioweapon" that does not need to eat, a trait the Nozama chairman famously scorns as the mark of an inferior, substandard life form. Jun is no longer a person but a prototype for a new line of weapons.
Jun’s development, or rather his lack thereof, is central to his tragedy. He is incapable of growth or change, as his abilities and very existence are maintained and upgraded externally by the research team. Unlike other Amazons who struggle with their instincts, he is static, a perfect weapon that cannot evolve. This becomes his ultimate weakness. While he feels no pain, his body is still subject to damage. In his final battle, the combined assault of Alpha, Omega, and the gunfire of the extermination squad inflicts more trauma than his systems can handle. As his body begins to melt down from the accumulated damage, he panics, his cold facade cracking for a moment before he is fatally pierced through the chest by Mamoru. After his body melts away, the members of the extermination squad honor the memory of the person he once was by placing a five-yen coin, a symbol of good fortune and connection, into the remains of the Sigma-type, a final act of friendship that closes his tragic narrative.
As Kamen Rider Amazon Sigma, Jun possesses several notable abilities that set him apart. His physical parameters, including a punching force of 23.3 tons and a kicking force of 29.1 tons, surpass those of the first-season Alpha and Omega. His body structure includes a Sigma Header antenna for sensing enemies and a Converter Lung that can render internal damage nearly ineffective while converting heat and wind into energy. His arm and leg blades, the Shell Break Arm and Shell Break Leg, are powerful cutting tools capable of breaking through thick rock. His signature finisher is the Violent Strike, a leaping corkscrew kick identical to Amazon Omega's. However, his defining ability is his complete lack of pain sensation, courtesy of his modified Amazons Driver, allowing him to fight relentlessly. The fatal flaw of this ability is that it prevents him from recognizing the extent of his own injuries, leading to his eventual destruction. Furthermore, as a Sigma-type sustained by advanced cells, he has no need to consume protein, making him self-sufficient but entirely dependent on his handlers for repairs and upgrades.
Jun’s fate took a tragic turn during an encounter with a former teammate, Ryusuke Otaki, who had lost control and transformed into a cannibalistic Dragonfly Amazon. In a moment of hesitation, Jun was attacked and fatally wounded by Ryusuke. Rather than expressing anger or despair, he accepted his death quietly, finding a small measure of solace in the fact that his life was ended by someone he once considered a comrade. His body was subsequently recovered in secret by Yugo Tachibana, a high-ranking official at Nozama Pharmaceutical.
Instead of being laid to rest, Jun’s corpse became the subject of a revived and unethical experiment previously shelved due to moral concerns: the transplant of a new, more potent strain of Amazon cells into a human cadaver. This process brought him back to a state of existence as a new type of being, classified as a Sigma-type Amazon, or the Fourth Type. He was reclassified as a product of Nozama Pharmaceutical's International Business Strategy Headquarters, a living biological weapon developed to surpass the older Amazon types. To complete his transformation, he was given a black replica of the Amazons Driver, a belt that copied the original’s function but added a crucial modification to block the sensation of pain.
As Kamen Rider Amazon Sigma, Jun’s personality underwent a complete and harrowing transformation. While he retained his memories of his past life and could still name his former colleagues, all emotional attachment and warmth were stripped away. The kind and strategic young man was replaced by an entity that operated with cold, machine-like efficiency. His love for chess twisted into a morbid game, where he would coldly announce how many moves it would take to defeat an opponent, treating living beings as mere pieces to be captured. He became devoid of empathy, capable of attacking his grieving friends without a flicker of hesitation, as seen when he callously threw Mamoru, who had rushed to embrace him believing he had survived surgery. He functioned as an unfeeling puppet, taking orders from Tachibana and the corporation without question, motivated solely by the directives programmed into his new existence.
Within the story, Jun, reborn as Amazon Sigma, serves as a tragic antagonist and a powerful physical threat to the two main Riders, Jin Takayama (Amazon Alpha) and Haruka Mizusawa (Amazon Omega). He was designed specifically to be superior to them, boasting greater physical statistics and the ability to ignore pain, which allowed him to continue fighting even after sustaining critical damage. In his first encounters, he overwhelmingly defeated both Alpha and Omega, nearly killing Haruka by piercing his torso. His role escalates the central conflict by demonstrating the corporation’s cruelty and willingness to sacrifice human lives for profit, turning a beloved former ally into a weapon.
Jun’s key relationships are defined by their tragic before-and-after nature. With the extermination squad, his revival transforms their grief into horror as they are forced to fight a ghost. Mamoru, in particular, shares a poignant moment, as his initial joy at seeing Jun alive is met with brutal violence. With his creators, namely Yugo Tachibana, he has no relationship—only a master-to-tool dynamic. Tachibana sees him as a successful commercial product, a "bioweapon" that does not need to eat, a trait the Nozama chairman famously scorns as the mark of an inferior, substandard life form. Jun is no longer a person but a prototype for a new line of weapons.
Jun’s development, or rather his lack thereof, is central to his tragedy. He is incapable of growth or change, as his abilities and very existence are maintained and upgraded externally by the research team. Unlike other Amazons who struggle with their instincts, he is static, a perfect weapon that cannot evolve. This becomes his ultimate weakness. While he feels no pain, his body is still subject to damage. In his final battle, the combined assault of Alpha, Omega, and the gunfire of the extermination squad inflicts more trauma than his systems can handle. As his body begins to melt down from the accumulated damage, he panics, his cold facade cracking for a moment before he is fatally pierced through the chest by Mamoru. After his body melts away, the members of the extermination squad honor the memory of the person he once was by placing a five-yen coin, a symbol of good fortune and connection, into the remains of the Sigma-type, a final act of friendship that closes his tragic narrative.
As Kamen Rider Amazon Sigma, Jun possesses several notable abilities that set him apart. His physical parameters, including a punching force of 23.3 tons and a kicking force of 29.1 tons, surpass those of the first-season Alpha and Omega. His body structure includes a Sigma Header antenna for sensing enemies and a Converter Lung that can render internal damage nearly ineffective while converting heat and wind into energy. His arm and leg blades, the Shell Break Arm and Shell Break Leg, are powerful cutting tools capable of breaking through thick rock. His signature finisher is the Violent Strike, a leaping corkscrew kick identical to Amazon Omega's. However, his defining ability is his complete lack of pain sensation, courtesy of his modified Amazons Driver, allowing him to fight relentlessly. The fatal flaw of this ability is that it prevents him from recognizing the extent of his own injuries, leading to his eventual destruction. Furthermore, as a Sigma-type sustained by advanced cells, he has no need to consume protein, making him self-sufficient but entirely dependent on his handlers for repairs and upgrades.