The Great Daimyo of the Ninja Clans has died in under mysterious circumstances, just as it happened with his predecessor, and his predecessor's predecessor and so on and so forth back to immemorial times. In order to take his place and serve the Shogun, the Daimyos of each clan have started the choosing process, and yes, you are said Daimyos. If you want to become the next great Daimyo you only need to manage one thing: be the last survivor.