Saburo Tenma originates as a student within Hope Town, a refuge founded by survivors of a devastating earthquake. Portrayed early as an overweight youth, he forms a fierce emotional bond with his teacher Keiko, whom he idolizes. When the motorcycle gang Hell’s Wind assaults the settlement, he fights back with a makeshift bow but relies on Jun, a vengeful ally wielding explosive arrows, for survival. A transformative shift occurs after contact with Violence Jack’s blood in battle, catalyzing accelerated muscular growth that reshapes his physique.

Inspired by Jack’s strength and protective nature, Saburo vows to mirror his heroism. Witnessing the town’s apathy during later conflicts hardens his resolve, spurring a decisive speech that reawakens Jack’s aid against Hell’s Wind—marking his first step from fragility to leadership.

Exiling himself to the wasteland, Saburo relentlessly trains by lifting boulders, forging a physique rivaling martial arts warriors. He clashes with the Slum King’s forces, crushing a samurai who attacks Keiko. Her fatal injury during another raid prompts a golden bird—summoned by Jack—to fuse with Saburo, amplifying his combat prowess to annihilate enemies. Her death leaves an indelible scar.

Rallying resistance against the Slum King, he commands armies seizing strongholds like Black Drake Fort, carving territorial boundaries in the fractured world. His strategies in large-scale battles reveal sharpening tactical intellect, coordinating assaults and deploying Jack’s interventions to tip conflicts.

Saburo’s journey culminates in founding the Tenma Army and securing his domain, solidifying his status as a pivotal power. His arc traces a path from wide-eyed idealism to hardened pragmatism, forged through loss, alliances, and unflinching confrontation with a brutal world.