TV-Series
Description
Gantetsusai Tamiya is a towering, physically imposing man in his early forties, standing at 222 centimeters with long, dark hair and a full beard. Known by the epithets Blade Dragon and Peerless of the Eight Provinces, his fearsome appearance and reputation as a legendary swordsman precede him. He wears a green kimono, and following a critical injury on the mysterious island, he loses his left hand and replaces it with a hook-shaped prosthetic.

Before becoming a death row convict, Gantetsusai was a respected samurai retainer who served a local lord after a life spent traveling the country to hone his swordsmanship. His downfall came from a moment of wounded pride. During a drinking party, his lord jokingly remarked that even Gantetsusai could not kill a real dragon. Enraged by this insult to his abilities, he left the party and, in a single, overwhelming stroke, cut through the lord's mansion gate, specifically destroying the dragon-shaped crest adorning it. This act of disrespect and property damage led to his arrest and death sentence, an outcome he views as a petty overreaction by a cowardly lord.

Personality-wise, Gantetsusai is bold, unruly, and seemingly carefree, embodying the image of a rough and pragmatic brute. He is driven by a massive ego and a thirst for battle and glory, projecting confidence in his overwhelming strength. However, this rough exterior conceals a sharp survival instinct and a surprisingly clear intuition that allows him to grasp the essence of dangerous situations quickly. While he is willing to use underhanded tactics to survive, he also possesses a spontaneous sense of honor and decency. He is notably tolerant and gentle toward women and children, treating the young girl Mei with kindness and genuine disgust upon learning of the abuse she suffered at the hands of the island's inhabitants.

Gantetsusai's primary motivation for joining the expedition to find the Elixir of Life is unique among the convicts. He has little interest in a pardon or literal eternal life. Instead, he seeks a form of immortality through legacy and fame. He desires for his name and deeds to be recorded in paintings, stories, and legends that will be remembered for generations, believing that a name which echoes through history is the true form of immortality. His secondary goal, should he win his freedom, is to return home and cut the mansion of the lord who condemned him in half.

In the story, Gantetsusai is paired with the Yamada Asaemon executioner Fuchi, a young man who specializes in autopsies. Their relationship is purely practical and mutually beneficial, a far cry from the typical executioner-convict dynamic. Fuchi treats Gantetsusai's wounds and fits him with his hook prosthetic, while Gantetsusai relies on Fuchi's medical skills and ability to communicate with the island's mysterious creatures. This partnership evolves into a rough camaraderie as they face the island's lethal threats together. He forms a temporary alliance with the protagonist Gabimaru after finding him unconscious, and the two develop a mutual respect based on their combat abilities. Gantetsusai's relationship with the Aza brothers, Chobei and Toma, is also significant; the younger brother Toma trained under him, and he encourages Toma to follow his own path.

Throughout his time on the island, Gantetsusai undergoes significant development. Almost immediately after landing, his survival instincts prove paramount. When a parasitic insect stings his left hand, sensing lethal danger, he instantly cuts his own hand off to prevent the parasite from consuming him. This act demonstrates his extreme pragmatism and refusal to be weakened by loss, as he continues to fight ferociously with a hook prosthetic. His development culminates in a desperate battle against a Tensen, a powerful immortal being named Tao Fa. Remembering the teachings of his master that discarding unnecessary things sharpens the self and the sword, and that a single precise cut is better than a flurry of wild attacks, he makes another brutal sacrifice. To stop relying on his other senses and better detect his opponent's energy, he gouges out his own left eye. This act of self-mutilation allows him to instinctively sense Tao, outmaneuver the Tensen's attacks, and land a decisive blow.

Gantetsusai's combat abilities are among the most formidable of any human character. He is a master swordsman whose raw physical power allows him to cleave through solid structures like a mansion gate with a single stroke. His technique is refined by years of training and a philosophy centered on discarding the unnecessary. Even after losing his left hand, his swordsmanship remains devastatingly effective. He can generate compressed air slashes with his blade capable of cutting through the enlarged bodies of his Tao-using enemies, a skill he acquires after a fierce fight that awakens his own Fire Tao. His notable techniques include the "Sky-Splitting Cut," a diagonal slash designed to bisect an opponent's torso, and the "Gate-Cleaving Slash," the legendary technique he used to destroy his lord's dragon gate. His fighting style is straightforward and explosive, seeking a single, decisive, critical hit rather than prolonged, wasteful exchanges.