The Deadlands — Ben Brown

Since the age of twelve, all Callum Wentworth has known is struggle and pain. His torments have galvanized him into not only a hard and unyielding man, but also a weapon.
His trials cost him dearly. He lost his family, friends, a hand … and almost, his humanity. He accepts these sacrifices so he can stop the spread of the Lingering. He accepts he has to do things that no man should, and now all his sacrifice and pain is about to pay off. Finally, he has the chance to make the undead pay for what they have taken from him.
The year is 1852 and America is split into two nations. One side has the living, the other, the undead. Beyond The Divide lays the Deadlands. A land bereft of life or hope. A land ruled by Lingerers … but it is time for the living to take the lands back.

This book also includes the bonus short story, king of The Undead.