Despite the name of the series, most of the characters are not samurai in the true sense of the word. The stories in the series take place in 18th-century Japan, during the Sakoku or seclusion period of Japan with great artistic license so that foreign-born characters and fictional monsters can also...
In early Japan, a man named Shiro Tokisada Amakusa preaches a heretic religion. Little does anyone know that Amakusa is really a servant of the evil Ambrosia, who took over Amakusa's body. Ambrosia wishes to shroud the world in darkness. Now, choose between 12 warriors (and 3 bonus characters) to fight for the honor of destroying Amakusa, and fulfilling a mission.