Killzone: Shadow Fall is a sequel that takes place 30 years after Killzone 3 events. Life on the Helghast home planet, Helghan had been left in ruins; however, the war still exists. The Interplanetary Strategic Alliance (ISA) allows Helghast refugees to resettle on planet Vekta. The Vektan and Helghast factions are living in a 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 story is seen through the perspective of Lucas Kellan, an agent of the elite ISA special forces branch known as the Shadow Marshals.