The movie opens up with a evil sorcerer participating in an evil ritual, using a naked girl. Several scenes with bad special effects later, we learn that this evil sorcerer is going to bring back to life seven of Japans greatest leaders (they are going to be REBORN FROM HELL, we know that because that phrase occurs every few lines, to remind us) so that they can lead a army of demons and bring about SAMURAI ARMAGEDDON. In effect, it is the equivalent of an evil sorcerer bringing Abe Lincoln back to life to lead a demon army to bring about "Soldier Armageddon". By the way, apparently the only way to get historical figured REBORN FROM HELL is to get them to have sex with strange women, at what point they turn into a zombie/demon and go sit in a closet in the evil sorcerer's cave, waiting patiently for their turn to fight the hero
The only hope for the world is a lone one-eyed Samurai, Jubei. Jubei runs in to a reborn demon, kills him, then decides to save the world and stop SAMURAI ARMAGEDDON. If a one eyed zombie slaying samurai fighting historical icons isn't great enough, there is also the fact that the movie makes about no sense at all. After the evil ritual it goes straight in the middle of a fight, sticks in characters that the viewer apparently already should have known, and half of the seven demon leaders have already been REBORN FROM HELL. Simply mind-blowing.