Katsumi Orochi, son of a circus lion tamer, witnessed his father's fatal mauling. Doppo Orochi adopted the boy after seeing him calm the escaped lion while grieving. This early tragedy set Katsumi on a path to martial arts under Doppo's guidance. Introduced as a highly skilled yet arrogant prodigy of Shinshinkai Karate, Katsumi bore the moniker "Lethal Weapon." His overconfidence surfaced during the Maximum Tournament, where he disrespected opponents like Kaoru Hanayama, dismissing him as a gangster. That fight showcased Katsumi's Mach Punch—a technique developed with Doppo to break sound barriers—but also his flaws. He faltered against Hanayama's resilience until spurred by his dojo seniors. Victory came at the cost of severe injuries, revealing his early reliance on raw power over tactics. Traumatic encounters reshaped him. Brutally defeated by death row convict Dorian, Katsumi retaliated with uncharacteristic vindictiveness, dousing Dorian in gasoline and setting him alight. This marked a turning point. Subsequent challenges fostered greater maturity; he began acknowledging opponents' resolve, conceding to Hector Doyle and sumo wrestler Shishimaru due to their refusal to yield. This evolution reflected a deeper understanding of martial honor beyond victory. Physically, Katsumi endured transformative injuries. His fight against the prehistoric Pickle culminated in the loss of his arm after deploying the Hitless Blow, an ultimate technique sacrificing limb integrity for destructive force. This led to a pivotal enhancement: Retsu Kaioh's arm was surgically grafted onto his body during *Baki-Dou II*, restoring his combat functionality. Relationships defined his journey. His bond with Doppo resembled a friendly rivalry more than a traditional father-son dynamic; both competed in the Maximum Tournament to prove their karate's superiority while indirectly caring for each other. Katsumi maintained respect and affection for his biological mother, expressing gratitude for her role in his existence. He explicitly valued all four parents—biological and adoptive—equally. As Shinshinkai dojo leader, Katsumi demonstrated responsibility toward his students, who reciprocated with loyalty, mobilizing to support him against Pickle. His initial ambition to defeat Yujiro Hanma gradually shifted toward broader self-mastery, culminating in a calmer, more composed demeanor post-Pickle. This maturity coexisted with unwavering drive; every battle became an opportunity for growth, fueling his relentless pursuit of rematches against foes like Retsu Kaioh.