Inosuke Hashibira is a Demon Slayer Corps member who survived Final Selection alone prior to the main story. His early life involved violent separation from his mother, Kotoha, who fled domestic abuse to Doma's cult. Discovering Doma was a demon, Kotoha sacrificed herself by throwing infant Inosuke off a cliff to save him; fostered by wild boars, this led to limited grasp of human society, illiteracy, and frequent name mispronunciations. He possesses a muscular physique and a strikingly feminine face featuring pale green eyes and black hair fading to blue at the tips. He modifies his Demon Slayer uniform with a hollowed boar's head mask—adjusted for visibility—as tribute to his boar foster mother, adding deer fur at his waist and bear hide leggings that expose his feet. Initially hostile and solitary, Inosuke displays extreme aggression, overestimating his strength and instigating fights. Early battles, like against Kyogai in the Tsuzumi Mansion, reveal his instinct-driven combat. A pivotal shift occurs during the Mount Natagumo Arc, where near-fatal wounds from the Father Spider Demon and rescue by Giyu Tomioka shatter his perceived invincibility. Later interactions with Tanjiro Kamado and Zenitsu Agatsuma forge camaraderie, gradually teaching him cooperation and strategy. He develops fierce loyalty, refusing to let allies die and unleashing fury when they are harmed, attacking Doma for killing Shinobu Kocho and later learning Doma also murdered his mother. Inosuke originated Beast Breathing, a self-taught swordsmanship style mimicking animal movements, wielding dual serrated blades often deliberately chipped for a sawing effect. His physical capabilities include enhanced flexibility enabling joint dislocation and organ shifting—evaded Gyutaro's fatal strike in the Entertainment District Arc—and extreme touch sensitivity detecting air vibrations for spatial awareness. He also possesses poison resistance, surviving Upper Rank Six Gyutaro's toxins, though this nullifies medicinal antidotes. His combat skill advances through arcs like Hashira Training, mastering techniques like Total Concentration Breathing faster than peers and learning Repetitive Action after a single observation. Key battles mark his growth. In the Mugen Train Arc, he aids in defeating Lower Rank One Enmu by identifying weaknesses despite initial comedic confusion about trains. During the Infinity Castle Arc, he intervenes in Kanao Tsuyuri's battle against Doma, harnessing rage upon learning Doma consumed his mother to help coordinate Doma's defeat. Against Muzan Kibutsuji, he demands restitution for slain comrades and thwarts Muzan's escape, revealing his evolved justice. His emotional progression culminates grieving injured allies and tearfully supporting Tanjiro's humanity after Muzan's corruption attempt. Inosuke's journey transitions from solitary ferocity to valuing collective strength, driven by relentless will and intuitive combat genius. His legacy merges primal instinct with hard-won humanity, cementing his enduring role in the Demon Slayer Corps' pivotal conflicts.