Smoke and Summons by Charlie Holmberg 

As a human vessel for an ancient spirit, Sandis lives no ordinary life. At the command of her master, she can be transformed against her will into his weapon—a raging monster summoned to do his bidding. Unlike other vessels, Sandis can host extremely powerful spirits, but hosting such creatures can be fatal. To stay alive, she must run. And in a city fueled by smoke and corruption, she finds a surprising ally… Read more.