Emergence Day or E-Day was a swift, full-scale, coordinated and unprecedented planet-wide assault on the surface of Sera initiated by the Locust Horde. Every single major human city on the surface of Sera was attacked from the subterranean, using both bio-engineered weapons and stolen human technology. All breaches were along the ground line, in what was a campaign of rapid dominance.
It was a textbook military invasion. There were massive casualties everywhere the Locust arrived; over a quarter of the total human population died on that very first day. The Locust Horde was able to deploy huge numbers of their forces into all major cities on the surface at once. The Locust rapidly dominated the humans in their massive assault and were able to defeat all organized human resistance for over a year.
They had used the spoils of war and victory to gather all available military and civilian technological equipment and resources to use against the COG and the few UIR nations that still existed after the Pendulum Wars. The Locust Hordes onslaught and assault continued for a year until the Hammer of Dawn counterattack, in which the Hammer Of Dawn technology was deployed under the newly elected Chairman Richard Prescott.