Daniel Abraham 
Seasons Of War 
Book Two of The Long Price

The poets and their magical andat have protected the cities of the Khaiem against their rivals in Galt for generations. Otah, Khai of the Winter City of Machi, has tried for years to prepare his people for a future in which the andat can no longer be safely harnessed. But his warnings have been ignored, and now it’s too late.A ruthless, charismatic Galtic general believes he has found a way to strip the andat of their power. If he is wrong, Galt will be destroyed. If he is right, the Khaiem will fall. Only one thing is certain: conflict is inevitable, and Otah and his old friend and enemy the disgraced poet, Maati, must fight a desperate battle to protect their cities from slaughter. These two men, bound together by shadow and betrayal, will bring the world to the edge of a cataclysm unlike anything either side had imagined. For if the cost of war is high, the price of peace may be unimaginable . . .