Ashes of Dearen, Book 1 — Jayden Woods

A red-eyed assassin, an unready princess, a sadistic politician, and an adulterous queen all desire the secret behind a magical dust known as safra. Safra is said to bring happiness, but these characters' desperate attempts to obtain it will cost them all dearly. Their salacious and violent deeds bring three great nations to the brink of warfare. And little do they know, their scrambling efforts are being carefully watched by a much greater power: the gods behind the beguiling drug that ensnares them all.