Helghast Infantry during the Invasion of Helghan.


ISA forces defending Vekta.

The Second Extrasolar War also known as the Second Helghan War was the second major war between the ISA/UCN and the Helghast.

The war began in 2357 when the Helghan Empire, under the control of Scolar Visari, sought to dramatically expand itself by invading Vekta, then invading Earth once Vekta was conquered, and destroying the UCN. Any opposition from the ISA-controlled systems would be crushed in a subsequent invasion of all other Human colonies.

Invasion of VektaEdit

UCN cruiser

Earth Fleet ending Visari's plans for the SD Platform.

The first stage in the Helghast's expansionist plans was the reclamation of the ISA controlled world of Vekta. Initially the ISA suffered massive casualties and territorial losses on Vekta after the Orbital Defence Systems 'malfunctioned', opening up the planet to a mass invasion force, and with a pair of high ranking double agents, the Helghast managed to take large swaths of territory and inflict severe ISA casualties in a savage blitzkrieg. However, due to the actions of Jan Templar and UCN reinforcements, the invasion was eventually halted and pushed back, and the few remaining Helghast of the 3rd Army were forced to fall back and regroup.


-Initial Strength

36,000 Vekta ISA
300,000 Helghast Third Army


-Tenth month (Estimated or projected)

11,500 ISA casualites (VEKTA TODAY Statistic)
Unknown Helghast Killed/POW

Invasion of HelghanEdit

Second Extrasolar War

ISA Avenger Convoy under assault.

Two years later, the Helghast homeworld of Helghan was invaded by the ISA in November 2359 in an attempt to capture Visari and establish an easy-to-control puppet state. However, the ISA invasion was to fail due to unexpected fierce resistance from the Helghast, culminating in the nuclear devastation of their own capital, killing the ISA soldiers attacking it, and in turn the bulk of the ground invasion force. Also, the destruction of many of their cruisers, including the flagship New Sun, and finally the death of their fleet commander Colonel Jan Templar, by a large counterattack led by Colonel Radec has handed dominion of space and air to the Helghast, who bombarded the remaining ISA forces and overwhelm the few remaining ISA cruisers.

Operation Archangel was the largest operation of its kind and larger than even Operation Barbarossa, the German invasion of the Soviet Union during World War II, in terms of total combatants. The ISA spent two years building up it's fleet and military strength, while also finally concluding operations against the remnants of the Helghast Third Army on Vekta. Because of the idea that the ISA’s own surge in sheer size and military might would damage the morale of the Helghast, the ISA would send nearly all ISA personnel to Helghan, with token forces left behind to continue to provide security on ISA colonies.


Total Strength

12 Battle Groups

288 ISA Crusiers

2,160,000 Total ISA Personnel

- 1,440,000 ISA Marines, ISA Regulars and ISA Legionnaires

Per Wave

4 Battle Groups

96 ISA Crusiers

720,000 Total ISA Personnel

- 480,000 ISA Marines, Regulars and Legionnaires


Over 97% of invasion force destroyed (Over 2,100,000 ISA troops lost)


Total Strength

Possibly 25 million Helghast troops throughout Helghan

- Possibly 16 million held in reserve for counterattack

Initial Strength

Possibly 9 million Helghast troops active on Helghan

- Possibly 2.5 million within Pyrrhus


Possibly 22.5 million Helghast troops throughout Helghan

- Possibly 16 million from reserves/reinforcements


Over 99.99% of the Helghast Army or possibly close to 25 million after Terracide

Personnel numbers from both sides by 2356, one year before the Second Extrasolar War could have possibly been 200,000 personnel throughout the ISA which governs billions of inhabitants across many planets, while the Helghast are strong believers in Attrition warfare, could of possibly have had 9 million personnel from a population of just 2 billion Helghasts.

Killzone2 screen21

ISA forces in action on Helghan's bleak urban slums, as part of Operation Archangel.

Finally, Scolar Visari, the ambitious emperor of the Helghast and the objective for the entire campaign, was gunned down by ISA soldier Rico Velasquez before he could be taken into custody, causing the ISA to stage a frantic evacuation, which quickly devolved to a total rout, in a hurried and unsuccessful effort to withdraw from Helghan. Roughly six months after their defeat on Helghan, the Vektan Government capitulated to the Empire, formally ending the war in a status quo ante bellum as neither side could counterattack after that time, although the Helghast government played it off as the Empire's victory. However, conflict persisted between the Empire and ISA remnants on Helghan. 

Helghan's Civil WarEdit

In the wake of Visari's death, a political conflict over who will assume the role of Autarch was waged between Admiral Orlock of the Helghast Military and Jorhan Stahl, influential chairman of the private weapons manufacturer, Stahl Arms. As the remnants of the ISA fought to survive, Stahl developed weapons using irradiated petrusite gathered from the Pyrrhus nuclear blast zone, such as a new Arc Cannon or irradiated petrusite-based perimeter defenses and energy shielding. In particular, an experimental flagship built by Stahl carried hundreds of missiles whose warheads were filled with irradiated petrusite and, alongside a massive Helghast invasion fleet, planned to eradicate all life on Earth by saturating the entire planet with the new petrusite missiles.

However, the political struggle between now-Autarch Orlock and Jorhan Stahl began to escalate, with successful operations conducted by the ISA remnant only making the situation worse. Eventually, the political conflict came to a climax aboard a Helghast space station, resulting in the death of Autarch Orlock and the Helghast race being plunged into civil war. This allowed the remaining ISA forces to destroy Stahl's cruiser with hijacked Helghast strike fighters, causing it to plummet to, then explode in low orbit over Helghan. The cruiser's destructive payload of irradiated petrusite missiles then detonated due to secondary explosions, with the resulting wave of energized radiation incinerating the entire Helghast invasion fleet, a large space station, and violently irradiating all life on Helghan. Managing to avoid the cataclysmic explosion in time, the remaining ISA troops onboard the hijacked strike fighters then made their way back home to Vekta.



The war ends with Helghan's destruction.

The Second Extrasolar War was now at an end. With the devastation of the Helghast species and complete destruction of their military, industry and leadership, the ISA have emerged as a pyrrhic victor, despite a near total loss of their military resources and personnel.

With the ISA down to possibly around 100,000 personnel from a peak of two million and possibly as little as 6 ISA cruisers out of the 288 cruisers in the ISA Fleet during the Invasion of Helghan. While secretly a few thousand Helghast soldiers hid in underground bunkers on Helghan.


The flight to Vekta, and so ends the war.

The surviving Helghast and their remaining ships were given an escort to Vekta by the remaining cruisers in the ISA fleet. After having relocated to Vekta, some Helghast exacted small amounts of revenge on the humans living on their half of the planet before the government decided to evict all non-Helghast beings from their territory. The Helghast and human communities are then separated by a massive wall in Vekta City, tensions run high, putting the opposing factions in a cold war scenario and setting up the events of Killzone: Shadow Fall.

See alsoEdit