The manga is about the Sengoku Jidai (Warring States Period) of Feudal Japan. The rulers of the land - Daimyo - and their servants - Samurai - fight to get the rule of all Japan. Especially, the most powerful ones are the Devil King Oda Nobunaga of Owari, the Tiger of Kai Takeda Shingen, the Dragon of Echigo Uesugi Kenshin, the Hojos of Odawara Castle
