6A team of super-skilled criminals roams a science-fiction Wild West, each with their own reason to hunt for the ultimate prize: the 12 Rings of the Dead, which can raise the dead and grant eternal life.

Somewhere in the desert lies the world's greatest treasure: the 12 Rings of the Dead, the only source of the mysterious substance Zombie Powder, which can raise the dead and grant eternal life. Into this world stalks Gamma Akutabi, a man with a metal arm and a six-foot chainsaw, cybernetically enhanced master of the legendary martial art . But it takes more than one man to find the ultimate prize. You need a team: super-gunman C.T. Smith, knife-slinging teenager Elwood, and brilliant (and impossibly big-breasted) journalist Wolfgangina. Against an army of crooks and killers, against runaway trains and superpowered madmen, they'll need all their skills...but the most dangerous thing in the west might be the Rings themselves... All volumes except the first also contain a bonus short story by Tite Kubo: Ultra Unholy Hearted Machine (vol. 2), Rune Master Urara (vol. 3), and Bad Shield United (vol. 4).

A locomotive races across the desert, with a human body fused to the engine...the body of Wolfina's brother Emilio, one of the hosts of a Ring of the Dead! With no help in sight, Wolfina fights alone to free her brother...but can anything save him from a fate worse than death? Includes a special bonus story, Bad Shield United!