Military action
The fourth and final draconic war was the most devastating of them all, ending in the annihilation of almost all true dragons.
Continuing the research that created kobolds and combining this with the magic of Yotunoid forms, dragons began investigating ways to permanently eliminate their enemies using transformation. The resulting biomagical weapons resulting from this research unleashed devastation on the environment. In the final years of the conflict both sides were simultaneously engineering a magical virus that would selectively target the genetics of chromatic or metallic dragons respectively, mutating the affected creatures into kobolds. Dragons were believed to be too suffused with magic to be simply killed by such a weapon. Unfortunately for all dragonkind, including those that remained neutral in these wars, the first test of this weapon went horribly wrong.