Looking for title: after-death fantasy type

I cannot recall much about this book or series other than that it was a purgatory-like world. The H is a guard of some sort employed or reporting to the angels, I think, and h was human. Heroine is in this purgatory looking for someone. There is some sort of war going on between the angels and the world is in chaos. Eventually H and h fall in love.

I’m not even sure if it is a romance, but I remember it as one. It has to be probably at least a decade old as I don’t have any ratings listed in goodreads. But it would have been an ebook, if that helps.

Other bits I recall:
Weird building they go through that “eats” bad guys if the walls are touched (or something similar).
They had a name for the type of human the h was, she wasn’t a normal human, but can't recall what.
I “think” she was searching for her bff or brother(?)
May or may not be a series. I think it was, but obviously have forgotten a lot!
H isn’t an angel, I don’t think. No wings anyway. He carried a sword and wore armor I think...

Sorry for all the “I thinks” in there! Any help is appreciated!