Age: 19
Sagara Sanosuke left home at a young age to join the Sekihō Army (Sekihō-tai), leaving his father (Kamishimoemon), mother (Naname), and younger sister (Uki) who adored him. Years later, he returned to find out that his mother had passed away shortly after the birth of his younger brother, Ota, who looked up to Sanosuke for his bravery. Despite learning that his family name was now Higashidani, Sanosuke never used it himself. His sister became protective of their younger brother and father, who worked as a local merchant and farmer known for his fighting skills. After Sanosuke left again, Ota followed his brother's advice and trained at the Kamiya Kasshin-Ryū dojo to become strong.
The Sekihoutai fought for the imperial alliance during the end of the Tokugawa regime, with Sanosuke deeply admiring his captain, Sagara Sōzō, from whom he took the family name Sagara. The Sekihō Army's mission was to spread news of the tax reduction promised by the revolution. However, due to financial issues, the revolutionary government labeled them as frauds and scapegoats, leading to their execution. This betrayal was orchestrated by Shindō Tatewaki, a former officer in the imperial alliance. Sanosuke and his friend Tsukioka Katsuhiro were the only survivors.
Filled with anger and bitterness, Sanosuke became a mercenary known as "Zanza," named after his zanbatō sword. This katana, the heaviest ever made in the Rurouni Kenshin universe, originates from the Ōnin War and is now too worn to have an edge, making it useful only for smashing and crushing.
Hiruma Kihei and Gohei hired Sanosuke to kill Himura Kenshin, but after losing to Kenshin and learning about his no-kill philosophy, Sanosuke became a valuable ally. He later adopted a boxing-like fighting style, famous for the strength of his right fist. After his zanbatō broke in a fight, Sanosuke rarely used it again, except once more during the Jinchu arc to defend the Kamiya dojo.
At the end of the manga series, Sanosuke leaves Japan to avoid wrongful arrest and travels the world. Five years later, he sends a letter to the Kenshin-gumi, informing them that he is in Mongolia and will stay there before returning to Japan.
