Kenshiro is the central character of a post-apocalyptic narrative, known as the 64th successor of the ancient assassination art Hokuto Shinken. He is the youngest of four adopted sons trained by the previous successor, Ryuken, alongside his adoptive brothers Raoh, Toki, and Jagi. Originating from the war-torn Land of Asura, Kenshiro was sent to Japan as a child, where he was adopted and trained in the martial art. His biological older brother is Hyoh.

In terms of personality, Kenshiro is known for his strong sense of justice and compassion for the weak and innocent. While he may appear as a stoic and composed figure, he is deeply kind and emotionally intelligent, openly showing his feelings and mourning for the suffering of others. Before the main events of the story, he was more forgiving, but after experiencing great personal loss and the brutality of the world, he became merciless towards evil-doers who prey on the innocent. Even so, he maintains a fundamental decency, sometimes offering redemption to defeated foes, though typically only after ensuring they can no longer cause harm.

Kenshiro’s primary motivation evolves from a personal quest for revenge and rescue into a broader mission to protect the defenseless. His journey begins after a rival named Shin, instigated by Jagi, defeats him, carves seven scars on his chest in the shape of the Big Dipper, and kidnaps his fiancée, Yuria. After recovering, Kenshiro sets out to reclaim Yuria, and along the way, he takes in two orphaned companions, Bat and Lin. Following his initial confrontation with Shin, Kenshiro vows to use his skills to protect those who cannot protect themselves, earning him the title of Savior of the Century's End. His role in the story is that of a wandering hero who brings order to a chaotic world, facing not only common thugs and gangs but also rival martial artists, including his own adoptive brothers who have abused their power.

Key relationships define much of his journey. His bond with his fiancée Yuria serves as his initial driving force. His four adoptive brothers represent different paths and philosophies: Raoh, the self-proclaimed Conqueror of the Century's End; Toki, who uses his abilities for healing; and the treacherous Jagi, whose jealousy instigates much of Kenshiro's early suffering. His relationship with his companions Bat and Lin provides him with a surrogate family and a connection to the innocent people he strives to protect.

Throughout the story, Kenshiro undergoes significant development. He begins as a man seeking personal revenge but matures into a true guardian of humanity. He masters the ultimate technique of Hokuto Shinken, Musou Tensei, which can only be achieved by one who has known true sadness. After reuniting with a dying Yulia, he spends her final years with her before continuing his solitary journey. In later arcs, he travels to his homeland, the Land of Asura, to confront his past and his blood brother Hyoh, finally taking his fallen brother Raoh’s son, Ryu, under his wing as a student before resuming his wandering life.

Kenshiro’s notable abilities are rooted entirely in Hokuto Shinken, an ancient martial art that targets the 708 pressure points (keiraku hiko) of the human body. By striking these points, he can cause a variety of effects, from explosive death and bodily dismemberment to healing injuries and illnesses. His most iconic techniques include the Hokuto Hyakuretsu Ken, a rapid-fire barrage of punches delivered with his signature battle cry, and the Musou Tensei, or Nil-Thought Rebirth, which allows him to become intangible and phase through attacks. He is also famous for his catchphrase, You are already dead, which he declares to an opponent after striking their pressure points, just before the fatal effects take hold.