A former Ishin Shishi samurai, Shibumi spent the years after the bakumatsu climbing the ranks of the Meiji Government until finally becoming Secretary of the Senate by 1876. However, greedy for more power, Shibumi began hiring hitokiri to eliminate problematic opponents within the government itself. It was he who was behind the Kurogasa murders in Edō, having hired Udō Jin-e and Akamatsu Arundo to carry them out, but upon discovering that the Hitokiri Battōsai had arrived in Tokyo and become active once more, Shibumi sought outside help from former Shinsengumi member-turned-assassin, Saitō Hajime. Unfortunately for Shibumi, Saitō turned out to be an undercover agent for Ōkubo Toshimichi, the Chief of the Department of Internal Affairs. After Akamatsu discovered this fact and reported it to his boss, Shibumi began plotting to bribe Ōkubo's secrets out of Saitō and take the Internal Affairs seat for himself, but before he could fully map out his plans, both he and Akamatsu were swiftly slain by the incorruptible Saitō.