based primarily throughout the japanese sengoku period, "onimusha: warlords" starts with the feudal lord nobunaga oda being killed during a battle. one of the prominent fighters, hidemitsu samanosuke akechi, receives a letter from his cousin princess yuki who is concerned about servants from her castle disappearing. samanosuke joins with the kunoichi kaede to rescue yuki and discover demonic creatures known as genma are the culprits. in order to defeat the genma, the oni clan grant samanosuke powers from their kind. across his fights samanosuke discovers the genma have resurrected nobunaga into serving their needs while intending to sacrifice yuki and an orphan named yumemaru to grant him more powers. samanosuke manages to save yuki and yumemaru and kills the genma lord, the god of light fortinbras. samanosuke's group then takes different paths.