Seta Soujirou is Shishio's right-hand man and one of his most dangerous assets—a teenage assassin trained from childhood to be emotionless and efficient. He's best known for his unnerving composure: always smiling, always polite, and completely detached from fear or anger. Behind that perpetual grin lies a carefully constructed mask, though he does share something genuine with Yumi, who's essentially a sister figure to him. He usually wears a blue kimono with white handguards.
That smile has a dark origin. Born in Kanagawa in 1861 as an illegitimate child, Soujirou endured constant abuse from his family—brutal beatings whenever he stumbled with chores like hauling rice. He learned early that a smiling face could outlast their cruelty; if he didn't react, they'd eventually lose interest and leave him alone.
Everything changed when he encountered Shishio fleeing from police. After witnessing Shishio kill the officers, Soujirou should've been next—except he was smiling. Shishio spared him in exchange for food and shelter, and more importantly, taught him a philosophy: only the strong survive. When his family discovered the arrangement and tried to murder him, Soujirou—now armed with a sword Shishio had given him—killed every last one of them. He was eight years old.
That ruthless efficiency makes him a nightmare opponent for Kenshin. Soujirou earned the nickname "Heaven's Sword" for his mastery, particularly his signature technique: shukuchi, a form of movement so fast it literally appears to shrink the distance between fighters. During his battle with Kenshin, he constantly references being "three steps below" or "two steps below" true shukuchi, each level faster than the last. At full power, shukuchi makes him completely invisible—even Kenshin can't track him. He's the only fighter in the series to land a clean hit on Kenshin's back, and he can dodge the supposedly unavoidable Kuzu-ryūsen.
He combines this supernatural speed with battōjutsu techniques similar to Kenshin's own style, creating his one signature move: Shuntensatsu. The attack is so fast that victims die before they even hit the ground.
Content compiled by AnimeList.moe from publicly available sources.
