Live action TV
Description
Hajime Nakamura is a character introduced in the latter half of Kamen Rider Ryuki, serving as one of the users of the Alternative system, a man-made imitation of the Kamen Riders. Before becoming involved in the Rider War, Nakamura was a graduate student and a member of Professor Ejima's staff at Lab 401, a research facility at Seimeiin University. He was absent on the day Shiro Kanzaki and Professor Ejima began fateful experiments that ultimately resulted in the deaths of all his colleagues in the laboratory. Learning of this catastrophe later, Nakamura developed a deep and consuming hatred for Shiro Kanzaki and, by extension, his sister Yui Kanzaki.

Nakamura's personality is heavily shaped by the trauma and loss he experienced. He is portrayed as emotionally impatient and openly aggressive, particularly towards Yui Kanzaki when she comes to the university seeking information about her brother. He blames her for the tragedy that took the lives of his study group, stating that Shiro Kanzaki "all but killed one of us" and that it was all for her sake. Unlike others who might seek to stop the Rider War for heroic or altruistic reasons, Nakamura's primary motivation is vengeance. He eventually joins forces with Professor Hideyuki Kagawa, another survivor connected to the lab who developed the Alternative system. While Kagawa aims to shut down the Mirror World and end the Rider War, Nakamura's goal is purely destructive: he wants to destroy Shiro Kanzaki's research and has no interest in being a hero.

In the story, Nakamura is the identity of the completed Alternative unit, while Kagawa uses the prototype, Alternative Zero. His role is to act as an adversary to the main Riders, but his conflict is deeply personal. He is introduced as a man willing to kill Yui Kanzaki to achieve his revenge, which puts him in direct opposition to Shinji Kido, the protagonist who fights to protect people and end the war peacefully. His key relationship is with Professor Kagawa, whose cause he joins, though their underlying motivations differ. He also shares a significant dynamic with Satoru Tojo, Kamen Rider Tiger. Tojo initially works with Kagawa and Nakamura but becomes disillusioned, judging Nakamura's vengeful spirit as unsuitable for the image of a hero. This judgment leads to a fatal confrontation where Tojo attacks and ultimately kills Nakamura while he is fighting Shinji Kido's Ryuki.

Nakamura's character undergoes a brief but tragic development. Consumed by vengeance, he remains single-minded until his final moments. As he is dying, he looks at Shinji and says, "You're wrong," though the ambiguity of the statement leaves open the possibility that he is either rejecting his own path or finally acknowledging the correctness of Shinji's ideals. His death serves as a stark example of how the desire for revenge corrupts and leads to ruin within the context of the Rider War.

As Alternative, Nakamura possesses notable abilities that mimic those of the true Riders. He transforms using a Card Deck and V Buckle created by Professor Kagawa based on Shiro Kanzaki's notes. His form is nearly identical to Alternative Zero, distinguished primarily by the black cables on his suit. Alternative is contracted to a cricket-like Mirror Monster named Psyco-Rogue. Using the Slashvisor on his right arm, Nakamura can deploy Advent Cards. Key abilities include the Sword Vent to arm himself with the Slashdagger, the Wheel Vent to transform Psyco-Rogue into a motorcycle called the Psycoroader, and the Final Vent, a devastating attack named Dead End where Alternative rides the Psycoroader into a spinning ram against his opponent. His physical parameters as Alternative include a maximum jump height of 50 meters and a punching power of 300AP.