Dire Straits by Megan Derr

More than twenty years ago, Bannick fled the place called No Man’s Land with no intention of returning. Now, though, he is a powerful red-collared Crown priest, his duty to fight the many dangerous creatures that plague the country, and exorcise the demons all too frequently summoned by the unwise.
Ordered out to contend with a likely dire, an undead monster difficult to stop, he instead finds himself facing off against the worst abomination of them all: a dire demon, which he can’t hope to defeat himself. Only a necromancer can stop a dire demon, but the nearest necromancer might not arrive in time…