Katsura Kotarou endured early tragedy when illness claimed his parents, rendering him and his grandmother homeless. From her, he learned a vital warrior's philosophy: survival and caution were paramount for leadership, demanding one be "both more cowardly and stronger than anyone else" to protect others. Following her death, his intellect secured a military school scholarship. There, he befriended Takasugi Shinsuke. Discovering Yoshida Shouyou's teachings, both abandoned formal schooling alongside Sakata Gintoki. In the Joui War, Katsura fought with Gintoki, Takasugi, and Sakamoto Tatsuma to rescue Shouyou from the Bakufu. Captured, they were forced to witness Shouyou's execution, carried out by Gintoki. The event scarred Katsura, yet his resolve against the regime endured. Post-war, he led a moderate Joui faction, employing strategic retreats and evasion that earned him the moniker "Runaway Kotarou." Initial tactics involved bombing Amanto embassies and government symbols, consistently reported as causing property damage without casualties, reflecting restraint. His methods evolved from overt violence to subtler rebellion, prioritizing intelligence gathering, embedding moles, and fostering anti-Bakufu sentiment through covert networks. This shift was influenced by Gintoki's rejection of continued war and Katsura's bond with Ikumatsu, a widow running a ramen shop. He developed a noted affinity for housewives, especially widows and unfaithful wives, tracing back to a childhood crush on a neighborhood widow. Public activities required frequent disguises—like "Zurako," "Captain Katsura," or "DJ Ozura"—though they often failed to fool pursuers like the Shinsengumi. Katsura blended eccentricity with tactical brilliance. Often perceived as lacking common sense—anthropomorphizing objects or misinterpreting basic vocabulary—he displayed acute intelligence in leadership and combat. He maintained a frugal lifestyle, favoring simple meals like soba and the snack "nmaibo," coupled with politeness shown through honorifics like "dono" and gift-giving to avoid offense. He was consistently accompanied by Elizabeth, an enigmatic duck-like companion communicating via signboards. Combat showcased masterful swordsmanship honed under Shouyou, augmented by enhanced strength, speed, and endurance proven against foes like Neptune Shoukaku. His ingenuity extended beyond martial skill: he engineered explosives, hacked communication systems, repurposed everyday items like Famicom cartridges as weapons, and incorporated indigestion-inducing food into his fighting style. He also possessed a unique immunity, absorbing viruses to bolster his immune system, occasionally transforming him into "Ill Smith." After the Bakufu's collapse, Katsura initially served as prime minister during reconstruction but later resumed underground activities. His final portrayal depicts him continuing as a vigilante, balancing revolutionary ideals with protecting Edo's citizens. Historically, the character draws inspiration from Katsura Kogoro (later Kido Takayoshi), a Bakumatsu-era figure known for eluding capture, mirroring the "Runaway Kotarou" persona.