Occurring sometime before the first game, the Great Destruction is the event which forced humanity to seek shelter in the underground cities. A Great Destruction of some kind is an integral part of the backstory for each generation of games in the series with the exception of Generation 4, which occurs before one.
Armored Core Original UniverseEdit
At the end of the Thirty Years War, humanity was so ravaged that it was forced to seek sanctuary underground. Many technologies such as the Armored Core and Human PLUS are from the above ground civilization that existed before the Great Destruction.
Armored Core 3 UniverseEdit
Armored Core 4-5 UniverseEdit
The Great Destruction occurs at the end of the ORCA Rebellion in Armored Core for Answer. Kojima Particle radiation had begun to ravage the planet's surface, making many areas inhospitable. A lone LYNX managed to redirect power from Arteria Facilities to activate several Anti-satellite batteries across the globe, clearing a path into space for mankind to escape the planet at the cost of hundreds of millions of lives that had been aboard the Cradles - large, flying colonies that had previously been dependant on the Arteria Facilities to remain airborne. Shortly after this, the survivors would leave behind the Towers and many automated drones, including at least two A.I.s. Armored Core V and Verdict day take place hundreds of years after these events, and the traces of this devastating event can still be found in the post-apocalyptic landscapes - destroyed Cradles and Arms Forts , the Towers, heavy Kojima Contamination in many areas (though this has died down to manageable levels as of Verdict Day), and armies of automated drones, still fully functional. This marks the first time in Armored Core history that the events both preceeding and following the Great Destruction can be witnessed.