During the final years of the Age of Chaos, as the erstwhile ruling empires of the world crumble and fall, a major shift in power takes place. Needing lots of resources to fuel armies and safe populations from extinction, all people, nations and factions try to secure access to the vast treasures under the earth, mainly in the areas mined by dwarves for as long as they exist.
Colonia, sensing the coming lull in geopolitical power, quickly sends troops all over the world to secure as many of these resources as possible. The Drow Kingdom, noticing this action, and realizing the necessity to react, mirror this strategy from their side, knowing that even the some of the resources they have had access to in the past, would otherwise come under control of the humans.
As both sides race each other to secure every last known resource not currently controlled by a force that can defend itself, they soon find themselves in conflict. Colonia responds with a worldwide propaganda campaign, calling on the evil nature of the Drow, and presenting themselves as the selfless saviors and protectors of the 'good' races. The Drow respond to this by presenting Colonia as a new form of the old empires that exploited the world and thereby caused all the misery of recent times.
Both sides now having secured support and basis for expansion, subsequently increase their mutual animosity and tension rises ever further. Both knowing however that all out war against each others heartland would be too destructive, they get into a war of skirmishes and battles fought in areas of other peoples, and often against the locals in stead of each other, lasting for many many years.