From that day on, the world was filled with despair

April 20, 2150 A.D., this day full of despair, pain and sorrow, this day will always be remembered in the hearts of every human being. This day is known in history as the "Nine Cities Crisis". Nine 'cities' that fell from the sky from outer space. The humans of the earth had already discovered them 10 days ago, during which the earth used all the methods to prevent the landing of these nine 'cities', and these nine 'cities' appeared without any signs at all, as if they appeared out of thin air, and the landing, as if programmed, was destined for the earth. After the landing of these nine 'cities', the population of the earth plummeted, because when these 'cities' landed, three of them landed in the sea, two were pushed into the desert by humans using rocket propulsion, and the remaining four landed on four continents. Before landing, under the convening of many major powers, the resources of the whole earth were concentrated to suppress the damage caused by the nine 'cities', but in the end, the earth's population was reduced by one-third. During this period, the global economy shrank severely, and human beings spent countless dollars, hundreds of billions of dollars on rocket propulsion alone.

Since three of them landed in the sea, a chain reaction was caused. Tsunamis and earthquakes in several countries have leveled buildings in many areas, and despite early evacuations, they have had a severe impact on the global economy.

Two months later, the city gate opened automatically, and after opening the city gate, tens of thousands of unknown monsters appeared, these monsters have no ability to think, and human bullets and bombs can only destroy their weakest monsters, and in the face of monsters that are obviously at a higher life level, human beings are like lambs to the slaughter, and the level of science and technology that human beings used to be proud of is useless.

In the second week of the monster rage, several major powers at the forefront of the earth in the level of science and technology finally used their secret weapons, Yulong Kingdom's Pangu Mecha Change II. to fight, this is the second appearance of Pangu Mecha after a certain year's war, Yulong sent a miracle team, this is the strongest military force in China since a certain year, the Nuwa fleet, Fuxi fleet, Shennong fleet of a certain elite force to integrate, this is the last hole card of Yulong country, in addition to Yulong also sent the most elite special forces force Long Yan troops.

Mili sent Aurora, a Goddess of Aurora fighter jet, equipped with hypersonic boost-glide missiles, cloudburst bombs, and electromagnetic railguns developed by Miri. The armored loader sent by the Thuro Kingdom is equipped with high-energy laser beam weapons and the recently developed Metal Storm (official name: Redeemer), the most lethal weapon Maozi has invented in recent decades. Kou Yang Guo uses the MEGA particle cannon and the SLEIPNIR mecha, as well as the super vibration cutter and the Yang electronic sniper cannon. The weapons used in the battle are the Staff of God, the space-based kinetic weapon RODS FROM GOD, and the Excalibur sword, which is loaded in the power exoskeleton mecha Arthur brilliant...... In this battle, the entire human race of the earth gathered and unleashed the strongest weapons without reservation. In this battle, humanity put aside all prejudices, and all humanity united.

The final result of this war was the defeat of mankind, because the follow-up could not support a large amount of expenditure, even if most of the operations popularized intelligent robot combat, but in the later stage, only real soldiers could be allowed to go into battle to kill the enemy, and the number of soldiers decreased rapidly. As of 2153, the total number of human beings has decreased significantly compared to 2150.

The economies of many countries collapsed, and the world entered the Great Depression. From 2154 to 2155, known as the 'Low tide', this year due to the collapse of the human economy and the invasion of monsters, many people were starved to death and froze to death, and the number of deaths in this year was about 400 million, not counting the number of monster killings, about 350 million people died.