Iliksis, Light Stalker, led a Devil’s strike time that used stealth to slip past the Last City’s defenses so they could plant explosives that would annihilate the entire Bannerfall Tower and a chunk of the Wall along with it. This would have led to the 3rd great assault on the City (the first 2 being Six Fronts and Twilight Gap), but was thwarted because everyone’s favorite Mary Sue god-slaying Guardian coincidentally was there at the same time searching for Gjallarhorn blueprints. Kabr, the Legionless, used his Light and Vex tech to create the Aegis Relic. Without the Aegis, The Templar and Atheon were literally unkillable, perfect and infinite in all time. Kabr created a way to kill the embodiment of time itself, the pinnacle of the Vex. In my opinion, this is the greatest feat any Guardian has ever achieved. Even killing Oryx comes second. The Choir. A group of Hive studied the “song of life” emanating from the Traveler. They reverse-engineered this song to vocalize death. One member of the Choir even managed to create a part that killed the director of the Choir. Then no more than 20 Choir members singlehandedly [b][i]killed a planet by singing.[/i][/b]