Master of Restless Shadows by Ginn Hale

Freshly graduated Master Physician Narsi Lif-Tahm has left his home in Anacleto and journeyed to the imposing royal capital of Cieloalta intent upon keeping the youthful oath he made to a troubled writer. But in the decade since Narsi gave his pledge, Atreau Vediya has grown from an anonymous delinquent to a man renowned for penning bawdy operas and engaging in scandalous affairs.

What Narsi―and most of the larger world―cannot know is the secret role Atreau plays as spymaster for the Duke of Rauma.

After the Cadeleonian royal bishop launches an unprovoked attack against the witches in neighboring Labara, Atreau will require every resource he can lay his hands upon to avert a war. A physician is exactly what he needs. But with a relentless assassin hunting the city and ancient magic waking, Atreau fears that his actions could cost more than his own honor. The price of peace could be his friends’ lives.