New Fist of the North Star

In a post-apocalyptic Earth, the water has become entirely toxic, except for some kept safe in a reservoir. A fortified zone has been created by a man named Sanga, he calls it The Lastland. A group of villagers have discovered safe water, and Sanga wants it. He and his band of killers go to kill everyone and steal it. As they do a mysterious man apperes out of nowhere, instantly killing some of Sanga's men. His name is Kenshiro... (Anime News Network)