Masao Mori is a high school student and a street punk from Tokyo. He purchases a valuable Yamaha FZR1000 motorcycle, often referred to as the katana model, along with a genuine katana sword. After acquiring these items, he transforms into a vigilante who patrols the roads, using his motorcycle and blade to attack criminals. His actions lead to him being called the Samurider, though a mysterious masked biker also appears in Sapporo, creating chaos among local motorcycle gangs and the police. Masao’s background as a rebellious youth from Tokyo’s streets shapes his confrontational personality and his motivation to take the law into his own hands. His development involves the conflict between his ordinary life as a student and his violent secret identity, as well as the consequences of his vigilante actions. He is defined by his aggressive resourcefulness, his connection to his motorcycle as a symbol of freedom and power, and his willingness to use deadly force against those he deems criminal. Key relationships include other characters who interact with him both as Masao and as the Samurider, though the specific dynamics are not extensively documented. His notable abilities are his skill in riding the FZR motorcycle and his proficiency with the katana, which he employs in street confrontations.