Mr Death
Alix E Harrow
What is a pscychopomp, I hear you ask?
pscychopomp -- A spirit, deity, person, etc., who guides the souls of the dead to the afterlife
Also, it's what Sam and his boss Raz are. I'm not going to count that as a spoiler, since you learn as much in the first paragraph of Mr. Death. In fact, there is not much I can tell you that would not be a spoiler. The name "Mr Death" comes from the poem Buffalo Bill's by EE Cummings.
And that, really, is all I can reveal without spoiling. It's a beautiful story and will take you only ten minutes to read. You should do that!
Mr. Death is a short story by Alix E. Harrow, and can be read for free here.