When I wrote Numen the Slayer, I added an interesting feature to the ashes dragons leave in their wake. Dragon fire is well known for incinerating anything and everything it touches. However, from all that death and destruction comes the promise of new life. Like ashes created by forest fires and volcanoes, the ashes left by dragon fire is great fertilizer. In fact, due to the magical properties of these ashes, Dragon Ashes is the best and most coveted fertilizer in the Gradaian Empire. Wherever a dragon unleashes its fire, farmers and traders are not far behind, waiting to claim their share of the ashes. One kilogram of Dragon Ashes is enough to fertilize ten acres of land for a decade. Because Dragon Ashes is such a coveted fertilizer, farmers usually make pacts with dragons. In exchange for a percentage of their livestock, dragons would burn wood to provide the ashes.
At the start of Numen the Slayer, dragons were all but extinct and most of the Dragon Ashes were used up. After Numen the Slayer, Dragon Ashes become mass produced by newly revived dragons. As the years go by and Dragon Ashes becomes more common, the various lands of the Empire become increasingly more fertile, which promises more plentiful harvests than in previous years.