Small Gods of Calamity by Sam Kyung Yoo

A tightly woven blend of myth, magic, and the ties of a found family.
Ghosts that speak in smoke. Spirits with teeth like glass. A parasitic, soul-eating spirit worm has gone into a feeding frenzy, but all the Jong-ro Police Department's violent crimes unit sees is a string of suicides. Except for Kim Han-gil, Seoul's only spirit detective. He's seen this before. He'll do anything to stop another tragedy from happening, even if that means teaming up with Shin Yoonhae, the man Han-gil believes is responsible for the horrifying aftermath of his mother's last exorcism.
In their debut novella, Sam Kyung Yoo weaves a tale of mystical proportions that's part crime-thriller, part urban fantasy.