Early History Edit
Throughout the course of their history the humans had many wars and crusades motivated by hunger, disease and religion. Humans have been divided into many Empires and civilizations like the Hittites, Sumerians, ancient Egyptians and the Roman Empire. By the 17th Century, Humans had divided into many permanent civilizations like the modern day Nations of China, Britain (which at the time was known as the British Empire) from which occupied nations began to be granted independence like the United States, Australia, India and so on.
World War 1 (1914–1918) Edit
By the early 20th Century the Human race had split into two main alliances, the Central Powers and the Triple Entente from which both powers fought for supremacy and dominance of Earth in a conflict known as World War 1, which ended in the Central Powers' defeat and the disbanding of the Triple Entente, and the creation of the League of Nations.
World War 2 (1939–1945) Edit
World War 2 followed with the League of Nations or the United Nations fighting the Third Reich (or Nazi Germany) and the Empire of Japan, the conflict lasted for six years but eventually led to the Axis Powers surrendering and the birth of many organizations such as the UN (United Nations), the EU (European Union), and NATO (North Atlantic Treaty Organization).
Cold War (1947-1991) Edit
The Cold War had started after WWII, with competition between Capitalism and Communism. Tensions between the United States (aided by NATO) and the Soviet Union (leading the Warsaw Pact) began. Although, there wasn't any direct military conflict, they fought proxy wars in Korea, Vietnam, Afghanistan and so on.
The Berlin Wall kept Germany divided. There was West Germany, which was under NATO, and East Germany, which was under the Warsaw Pact. Fears of "nuclear war" raised in both sides. The Cold War ended after the Soviet Union collapsed, creating 15 new countries, and when the Berlin Wall was taken down, with West and East Germany united again for the first time since 1945.
World War 3 (2055 - 2059) Edit
By 2055, Earth's fossil fuels have nearly run dry, and in desperation the nations of the world would scramble to claim them. As a result, World War 3 breaks out. The use of nuclear weapons is frequent, at first only tactical-scale but quickly escalates to devastating warheads on major population centers.
Stepping back and realizing their mistake, the remaining world powers begin to negotiate for peace. This peace results in the humans becoming a spacefaring race, a unified government being formed known as the UCN, And developing advanced technology to colonize other worlds and ensure Earth's survival.
Human technology is the most advanced in the Killzone universe. It is not known what level they are on, but it is assumed to be impressive if the colonies technology is inferior to theirs.