Hajime Saito is a skilled swordsman and a former captain of the Shinsengumi, a special police force in the late Edo period of Japan, in the anime series Rurouni Kenshin. Known for his cold demeanor and ruthless efficiency, Saito often follows his own code of conduct, famously known as 'Aku Soku Zan,' meaning 'Kill Evil Instantly.' Throughout the series, he maintains a complex relationship with the protagonist, Kenshin Himura, sometimes as an ally and other times as an enigmatic foe, challenging Kenshin's ideals and resolve.