This is a fantastic book written by Tite Kubo (the creator of Bleach) and this is the plot summery:
They say that if you find all twelve rings of the dead, you can obtain the power of imortailty for the living, or bring back someone from the dead. People who search for the rings are called Powder Hunters, and Gamma is one of them, searching for the power of imortality.
This is a funny book with a good story and can be very violent at times but without showing too much blood. In Volume one you do see a couple heads getting sliced off but who doesn’t like seeing that? Check it out ^_^