A classic samurai story, with all the gore of Gantz but surprisingly even more cruelty. Shigrui is a story of perpetual vengeance and suffering. The story follows primarily Seigen Irako and Gennosuke Fujiki as they meet and their hatred for each other grows.
While being anime, it flows mostly like a live action period drama. Animation primarily serves to permit the extreme amount of gore that is shown. If you're looking for something done more realistically, such as in the style of Monster, then Shigurui has much to offer.