From GOD'S WAR:
When Rhys crossed the great churning waste of the desert, he’d been running not toward his father but away, across the disputed border between Chenja and Nasheen. The sky had lit up every night with deadly green and violet bursts. The world had smelled of yeast and mustard and geranium. He had stayed as far from the contagion clouds as possible, but when he stumbled through Chenja and into the nearest Nasheenian border town, he was hacking up his lungs in bloody clumps, and his skin burned and bubbled like tar.