During the Bakumatsu period of the 1860s, a paramilitary force of elite samurai were commissioned to keep the peace. Starting as the "Roushigumi", they later rebranded to Shinsengumi, moving to Kyoto to back the shogun and keep an eye on revolutionaries.  

While defenders on the surface, their zeal evolved them into an uncompromising Secret Police. Their code was severe: if a unit's leader was fatally injured, the entire unit was expected to die defending him, disregarding other fallen members. Although they maxed out at around 300 members and lasted only five years, they played a key role in delaying Meiji's victory over Tokugawa. But they weren’t saints. Plagued by internal conflicts and occasional chaos, their legacy inspired popular anime like ‘Shine On! Bakumatsu Bad Boys!,’ ‘Peacemaker Kurogane,’ and ‘Hakuouki.’