Born in London to a British royal navy vice admiral father and a Japanese mother, formerly a tayu in Yoshiwara, Kanna Sakyounosuke is tasked with being the bodyguard of Katsu Kaishu, as part of a request from H.S. Parkes, the head of British mission in Yokohama, and is an extremely talented fighter, armed with two guns, each of the Remington New Model Army Conversion type.