After having been stymied by the PCs during the events of DHFEC I, Erasmus managed to succeed in rejoining the worlds of Order and Chaos into a single world, undoing his work from five thousand years prior. Believing the Joining would weaken Sre’Landa, Erasmus planned to take advantage to usurp her power and assume her power as the God of Magic.
The resulting destruction caused millions of deaths as the two mirror worlds collided. Fortunately the worst was averted by the efforts of Jalla Malachi who attempted to pull the entire population of the world into the Plane of Shadow. While the lives of most were saved this way, not everyone made it back to the material plane and those left behind became the Umbral.
The collision changed the shape of the continents, caused the overworld to begin to orbit around Templum, and sowed chaos among the kingdoms for generations as the surviving populations of both mirrors learned to live on a single world. Over time the two sets of magic disciplines were merged together, and now the people of Templum no longer recognize a difference.