The Third Purge
The third purge came in 312:Leviathan and started out silently before fully unleashing. Goblin raids increased as did dragon sightings, but nowhere near the levels of the past purges. Raids and burnings happened, decimating harvests and the smaller villages. Then the full horde came. Although Umore is behind all purges, the strategy of this one is traditionally attributed to Umvakere, the orc god of war.
All races, excluding atpians and serpents, were once again united against the darkness. Dwarven forges not only made weapons and armor but siege engines, bunkers, and dwarven shield walls at various gates. Scattered humans scouted ahead and reported on the movements of goblin hordes and dragon sightings, orcs charged into battles crushing skulls, and elves attempted griffin riding to combat the dragons more directly. The Amethyst Preservers also fought valiantly, but much of their oral teachings and traditions had been lost in the second purge and they were much greener and weaker.
In the end, it was the Magimancy alone that managed to seal the rift between the Essence Weave and the mortal world, and just as before the dragons fled and the goblin hordes were quickly exterminated.