Katsu Kaishu (1823-1899) was a real historical figure in Japan. He is famous for brokering a peaceful transition from the Tokugawa shogunate to the imperial Meiji period in 1868. As a child he had been attacked in the groin by a dog but survived. He was a master swords man but was very reluctant to kill.
The word "Bakumatsu" in the Japanese title means the period towards the end of the "tent" government. It refers to the last few years of the Tokugawa shogunate from1853 to 1867.