When Demons Walk (Sianim series)

From the #1 New York Times bestselling author of the Mercy Thompson series (Frost Burned, Night Broken) and the Alpha and Omega novels (Fair Game, Dead Heat)
Sham had spent most of her young life as a sorceress and thief, stealing from Southwood’s nobility to survive. Now she must face the greatest test of her skills…
A killer has struck Southwood, claiming the lives of nobles. Lord Kerim, Reeve of Southwood, turns to Sham for help. Posing as his mistress, she delves behind castle walls to find the killer. But this murderer is no mortal—and Sham must use all of her magical wisdom to send the demon away. Because the city of Southwood has nowhere to hide—and no time to run…