The Reapers are the Angels by Alden Bell
Older than her years and completely alone, Temple is just trying to live one day at a time in a post-apocalyptic world, where the undead roam endlessly, and the remnant of mankind who have survived, at times, seem to retain little humanity themselves.
Temple has known nothing else. This is the world she was born into. Her journey takes her to far-flung places, to people struggling to maintain some semblance of civilization - and to those who have created a new world order for themselves.
When she comes across the helpless Maury, she attempts to set one thing right, if she can just get him back to his family then maybe it will bring forgiveness for some of the terrible things she's done in her past. Because Temple has had to fight to survive, along the road she's made enemies - and one vengeful man is determined that, in a world gone mad, killing her is the only thing that makes sense . . .