From Destinypedia, the Destiny wiki
Kaga-Clipse was the moon of the Clipse homeworld and their military capital. When Emperor Calus' Loyalists arrived to bring the Clipse under his dominion, Valus Nohr invaded Kaga-Clipse with six-thousand warriors. After eight weeks of intense fighting the moon was conquered by Valus Nohr. Rull signed a treaty with Calus, arranging for a chosen selection of the Clipse population to be harbored safely in manufactured archologies where they would be free from want and have peace, while the rest were exterminated with the guns of Kaga-Clipse being turned upon the homeworld and engulfing the planet in a firestorm.