Live action TV
Description
Shin Kazamatsuri is the protagonist of the 1992 film Shin Kamen Rider: Prologue, a reimagining of the classic Kamen Rider concept presented as a horror-influenced science fiction story. Before his transformation, Shin is a professional and highly skilled motorcycle racer, having graduated from the Department of Physical Education at Johnan University and competed in international class races with aspirations of becoming a world champion. He is described as having an exceptionally high IQ of 250, being both academically gifted and physically adept. His motivation stems from a desire to use his abilities for a greater good; he volunteers to be a test subject for his father, Daimon Kazamatsuri, a geneticist conducting research intended to cure diseases such as AIDS and cancer. Shin is driven by a strong sense of altruism and trust in his family, willingly giving up his promising racing career for what he believes is a noble scientific cause.

Shin initially possesses a personality marked by optimism and a close connection to his loved ones, including his girlfriend, Ai Asuka, a nurse at the research institute, and his friend Takuya Yuki. However, his life unravels as he begins experiencing horrifying and vivid nightmares of a creature committing brutal murders, not realizing these are telepathic visions connected to his own genetic alteration. As he uncovers the truth, his personality shifts toward fear, apprehension, and a desperate struggle to maintain his humanity. The experiments, funded by a sinister syndicate, were not intended for medical breakthroughs but to create mutant cyborg soldiers. Furthermore, his father's partner, Giichi Onizuka, harbors his own mad ambition to use the grasshopper DNA fusion to create a new species over which he can rule as a god.

Shin's role in the story is that of a tragic, reluctant hero. He does not seek out conflict; rather, he becomes a fugitive caught between the syndicate that created him and the CIA agent, Sarah Fukamachi, tasked with eliminating the threat he represents. His primary motivation becomes one of survival and protection for those he loves, rather than a traditional heroic quest for justice. This is most powerfully exemplified after the murder of Ai Asuka, who is pregnant with his child. In her dying moments, she pleads with him to protect their unborn son, who has also inherited the mutation. This tragedy solidifies Shin's resolve, clearing his doubts and pushing him to embrace his power to destroy the syndicate and safeguard the last remnant of his family.

Key relationships are central to Shin's tragedy. His father, Daimon Kazamatsuri, is a source of both love and pain, as his naive involvement in the research directly led to his son's suffering. His bond with Ai Asuka is his primary anchor to humanity; her death is the catalyst for his final transformation into a warrior. The antagonistic relationship with Giichi Onizuka is unique, as they are linked through a shared mutation and limited telepathic communication, forcing Shin to witness Onizuka's murderous rampages. Ultimately, Shin's development is a tragic arc from a promising young man with a future to a solitary, mutated outcast. After defeating his enemies, including the Level 2 cyborg Goushima, Shin is forced to flee from both the syndicate and the CIA, carrying Ai's body into a dark tunnel. In a final moment of hope, he telepathically communicates with his unborn son, realizing the child is still alive within Ai and possesses the same powers, giving Shin a new reason to continue forward on his isolated path, a path that embraces isolation and forfeits his own happiness to protect others.

In his transformed state, officially classified as a Cyborg Soldier Level 3, Kamen Rider Shin is a heavily mutated, insectoid humanoid who stands nearly two meters tall. He lacks a traditional belt or transformation device; his metamorphosis is triggered by emotional spikes, particularly anger, which activate the grasshopper genes within his cells. His notable abilities are all biologically integrated. He possesses immense physical strength, with a punching power measured at 2.8 tons and a kicking power of 4.2 tons. True to his grasshopper nature, he has phenomenal leaping abilities, capable of jumping up to 114 meters in a single bound and running 100 meters in approximately 3.4 seconds. His primary offensive weapons are the High Vibration Nails on his fingers and the razor-sharp Spine Cutters on his forearms and legs, which can slice through metal and regenerate if broken. He possesses a rapid healing factor, allowing him to recover from injuries at a rate 5000 times faster than a normal human. His body is covered in chitinous armor five times stronger than ceramic, capable of absorbing 75% of physical impact. Despite his monstrous and ferocious appearance, he retains full control of his actions and can recognize loved ones, though his primary vulnerability is extreme heat, as he cannot withstand temperatures of 700-800 degrees Celsius for long periods.