Bisco Akaboshi, a Mushroom Keeper infamously branded a terrorist by authorities for dispersing mushrooms wrongfully accused of unleashing the Rust Wind, embarks on a desperate quest after his mentor Jabi falls gravely ill to the corrosive plague. Determined to save his father figure, he pursues the legendary Rust-Eater mushroom, forging an uneasy alliance with Milo Nekoyanagi, a skilled yet initially distrusted physician. Their partnership merges Bisco’s ferocious combat prowess with Milo’s healing knowledge, creating a resilient duo.

Marked by crimson-spiked hair, a fiery emerald gaze, and a scarlet tattoo beneath his right eye, Bisco dons cracked goggles and rugged attire shielded by a weathered white cloak against toxic winds. His signature bow launches spore-tipped arrows that erupt into fungal growths upon impact. He navigates the desolate landscape astride Actagawa, a colossal crab companion he regards as kin.

Brash and fiercely independent, Bisco wields tactical ingenuity in battle, exploiting environments and deploying explosive fungi to outmaneuver foes. His street-smart survival instincts offset his illiteracy and disdain for authority. Though notorious as the "Man-Eater," he guards a steadfast loyalty to Jabi and gradually lowers his defenses around Milo, shifting from solitary rebel to protective ally.

Pivotal moments include storming Imihama to secure Jabi’s treatment, clashing with enforcer Pawoo Nekoyanagi and manipulative official Kurokawa, and unraveling the Rust-Eater’s secret: its power demands Mushroom Keeper blood. Battling a concealed Rust infection, Bisco pushes onward, exposing Kurokawa’s propaganda machine profiting from public fear. His evolution from vengeful outsider to collaborative leader emerges as he accepts Milo’s aid and prioritizes communal survival over personal retribution.

Relationships anchor his growth: devotion to Jabi fuels his mission, while camaraderie with Milo mellows his abrasiveness. Contentious encounters with Pawoo blend rivalry with grudging respect, hinting at deeper complexities. Confrontations with Kurokawa unravel systemic greed, cementing Bisco’s defiance against oppression.

Trained under Jabi’s harsh mentorship, his proficiency in combat and distrust of power stem from a life forged in adversity. As Rust ravages his body, resilience and alliance with companions like Milo sustain him. His journey culminates in embracing unity over isolation, challenging corrupt regimes to restore the mushrooms’ true purpose as life-givers, not destroyers.