Ossuary Empire (2014)

From publisher blurb:

The Grand Stair stretches behind the scenes of the multiverse, the Doors upon its unfathomably vast span leading the way to gossamer worlds of limitless variety and infinite possibility. In this world, the gods are dead, but their bones remain the ultimate power.

Ossuary Empire is an exotic, exciting realm of shifting sands and sprawling cities, pulling itself back from the brink of apocalypse. A great and terrible war has extinguished the last of the gods known as the dîv, and in the void of their absence a dangerous secret has been revealed: the bones of these fallen deities are now the key to magic and the deadliest of weapons. The fight for survival and supremacy is on as thieves filch these precious relics from crowded bazaars and hashashin strike from the rooftops, while out in the desert the prophets whisper that something new is coming... they can feel it in their bones.