We Battle. We, #2

The emperor has vanished and usurpers hold the capital. Unaware of his sibling's fate, Sathriel must set aside his quest half-finished to take on the mantle of leadership. Portents are growing more concrete, but the witch doesn't have a plan to cope with the danger she helped Sathriel unleash. Across the ocean, another empire faces its own crisis. The last of their ruling line has died and his untried widow takes the throne, her cousins her greatest rivals.
All three of these sorcerers will find themselves in the witch's desert, where they learn the stunning history their peoples share. At its heart, the origin of the crisis threatening all of them.