History

The area we know as the "Killzone" AKA the Alpha Centuari System, starts with our planet in the near future plagued by World War III that inevitably ends with the use of nuclear weapons that destroy Earth almost completely. Technologically advanced enough, Humanity decides to leave Earth and create colonies on planets or satellites like the moon, while they search in space for other habitable planets. In this search are several organizations, including companies like the Helghan Corporation.

History after Earth

 * Main article&#x3A; Terran Era

Reaching Alpha Centauri
It does not take too long to find two planets in the Alpha Centauri system. Receiving the commission, the Company decided for Helghan to colonize them; Vekta (in honor of the company's president), a planet much like Earth to serve as the basis for all its activities, and a habitable but inhospitable planet, Helghan, that has too little strategic value but serves Vekta support.

First Extrasolar War

 * Main article&#x3A; First Extrasolar War

However, all other colonies begin to recognize the strategic power of Alpha Centauri and exploiting its advantage, companies are beginning to put the Helghan passage through the tax system and to profit from their privileged position. Of course, this opportunism eventually triggers jealousy among the various organizations, including the leading military organization, Interplanetary Strategic Alliance or ISA. In an impulsive action, ISA threatens Vekta with an embargo that they have ceased the right to dominate this territory (Vekta and Helghan). Refusing to accept this, the colonies on Helghan end up suffering a siege after offering very little resistance to the power of the strategic fleet of the ISA. Vekta is surrounded and eventually invaded by the ISA to expel the settlers from Vekta to the inhospitable planet Helghan. ISA takes care of Vekta enjoying all the strategic value of this planet and declared it their property.

Second Extrasolar War

 * Main article&#x3A; Second Extrasolar War

History would repeat itself, and just like World War I before it, the First Extrasolar War would lead to another war.

Invasion of Vekta

 * Main article&#x3A; Killzone

However, in Helghan stands a charismatic leader who takes advantage of the aftermath of the First Extrasolar War to form the Helghast Empire and prepares a fierce campaign to recover what is rightfully his: Scolar Visari. The ISA continues to assert its powerful military wing, even going undercover to sabotage the Helghast operations, and to completely annihilate the attempted invasion of the Helghast against their home planet.

Liberation of Vekta

 * Main article&#x3A; Killzone: Liberation

Vekta is again recovered by the ISA after intense battles on the ground that included some of the Helghast desperate attempts to kidnap key members of the ISA, that culminate in the expulsion of the finalization of Vekta Helghast.

Invasion of Helghan

 * Main article&#x3A; Killzone 2

Defeated but still resolute the Helghast continue their propaganda campaign as a driving force to break up the military power of the ISA. Eventually, the ISA troops decide to strike a heavy blow by invading Helghan and try to annihilate the rest of the resistance. But the fact that the Helghast people survive in such hostile conditions make them formidable adversaries. As Visari himself claims, the Helghast have become more than human. The ISA are going up against a motivated and powerful human force and also an entire planet inhospitable that makes your life harder.
 * Main article&#x3A; Killzone 3 Visari, the leader of the Helghast is gone, but the war is far from over. Helghast forces have mounted a devastating counterattack, prompting the ISA to smoke out evacuation of planet Helghan. As new Helghast battalions appear, armed with more powerful weapons, ISA forces find themselves outmanned, outgunned and surrounded however the remaining ISA forces hijack two fighters and manages to shoot down Jorhan Stahl's cruiser (the Helghast corporate chairman of Stahl Arms). Unwilling to let Stahl escape the cruiser, he drops a nuke on the falling cruiser, detonating the Petrusite weapons it was carrying above Helghan's atmosphere. The Petrusite engulfs the entire planet and wipes out almost everything on its surface. However, Stahl survived, crash landed on Helghan and is greeted by two Helghan soldiers.

Cold War

 * Main article&#x3A; Killzone: Shadow Fall

30 years after the Invasion of Helghan, life on the Helghast home planet Helghan has been left in ruins. The ISA allows Helghast refugees to resettle on planet Vekta. The Vektan and Helghast factions are living in Vekta City which is divided by a large security wall. The Helghast are fighting for their right to exist, while the Vektans are fighting for survival, leading to a "Cold War" between Vektans and Helghast.

The "Black Hand", a Helghast paramilitary terrorist group, was formed under Vladko Tyran, who became an antagonist, along with Lady Hera Visari (Scolar Visari's daughter) who has inherited her father's throne. By the end of Killzone: Shadow Fall, it is revealed that the main antagonist is Jorhan Stahl, who managed to survive the events of Killzone 3. Stahl met his demise by Vektan Security Agency director Thomas Sinclair.