Zeronus is a presumably ISA controlled colony that is not directly mentioned in the Killzone games, but it appears on advertisements in the Vektan Slums. In the posters, Zeronus is portrayed as a tourist world like Gyre, but on the posters it says: * 'Guaranteed Alien Free' * 'The only planet with extra oxygen for a real relaxed vacation' * 'Sun 24 hours a day'