Siege of Qikost

From Halopedia, the Halo wiki

The Siege of Qikost was an ancient and protracted civil conflict fought by the Sangheili, on their homeworld's moon Qikost. Little is known of the war, though during the fighting Warlord Nakada 'Zadum was able to craft and deploy the now-standard Elo'Nakada-pattern concussion rifle for the first time.[1]