Mors Obliviscens - Allyson McCollum

What happens after death? 

Flit has no idea who she is. She doesn't remember her name, how she got here, or where "here" is. When she encounters the Grim Reaper who tells her that she has died and is now in Purgatory-unlike other souls who pass on to Heaven or Hell-her only real option is to leave with him. He gives her a name and takes her with him to an abandoned cabin, where she tries to recover her memories. As she helps him retrieve the souls of the dead, she starts to wonder what really happened to her: Was she supposed to die? What happened to her family? Did someone kill her?

As they reap more passing souls and face new creatures, she has more questions than answers. There is a war brewing, and Flit finds herself caught in the threads of a battle between angels and demons, descending into the depths of Hell to save someone she thought was a myth. Will she help the angels and prevail? Or will she learn that the secrets of death are darker than she could've imagined?