Kiyosumi Katou emerged as a top disciple of karate legend Doppo Orochi before departing the Shinshinkai dojo, disillusioned by its perceived lack of rigor. His subsequent plunge into yakuza circles honed a brutal street-fighting ethos. Returning to Japan, he discovered the Underground Arena tournaments, reigniting his passion for martial combat. Notorious for arrogance and volcanic temper, Katou routinely clashes with rivals like Baki Hanma and Katsumi Orochi, yet maintains veiled reverence for Doppo. Though quick to mock others, he recognizes his own shortcomings compared to elite fighters, fueling an obsessive quest for validation. His combat style merges pragmatic brutality with improvised weaponry—rubber tubing and fishing line become tools to cripple opponents, as demonstrated against Dorian. Katou sports slicked-back black hair, an average build, and battle-earned facial scars. He favors casual tracksuits—colors shifting across adaptations—and dons traditional karate garb in formal matches. Early arcs depict him assaulting Shinshinkai students upon his return, flaunting disdain for orthodox training. During the Maximum Tournament, he serves as an analytical commentator, dissecting competitors’ techniques until his own match against Yasha-Zaru Jr. collapses into a no-contest due to external interference. His rivalry with Baki simmers with frustration, erupting when Baki dismisses his chances against Yasha-Zaru Jr., provoking violent retaliation. Later, he orchestrates Dorian’s downfall in an amusement park ambush alongside Atsushi Suedo and Doppo. Though sporadically aiding allies like Kanji Igari against attackers, Katou remains fixated on proving his worth through underhanded tactics. Narrative threads trace his internal rift between pride in karate as his sole achievement and acceptance of its limitations as a mere tool. Dorian’s hypnosis briefly warps this conflict into delusions of godhood, exposing latent insecurities. Post-tournament developments show him tentatively rejoining Shinshinkai under Doppo’s watch, yet his combative streak persists, underscoring a fraught mentor-student dynamic and ongoing philosophical struggle with martial arts’ purpose.