Wasteland Marshals Volume One

The world ended. Then things got tough.

Shane Collins and Lucas Maddox are the last two US Marshals after a global cataclysm that destroyed most of modern civilization. They're still on the job, fighting the good fight, although they're no longer fully human and maybe not entirely sane.
Witches and werewolves were not covered in their training as US Marshals. Then again, neither was the Apocalypse.
It's hard enough trying to navigate a new world of monsters, magic, and no decent takeout. Then there's the strange magic corrupting the land that affects them more now that Shane is tied to the collections of magical energy throughout the countryside, and Lucas has an ancient elemental spirit riding shotgun in his head.
Yeah, they never mentioned this stuff in training.
The Wasteland Marshals series is an action-packed near-future post-apocalyptic thriller full of grim ghosts, legendary creatures, shifters, and elemental spirits, brave survivors, loyal friends, and found family. This omnibus includes the first four novellas: Wasteland Marshals, Witch of the Woods, Ghost of the Past, and Shutdown Crew.