From the grimoire- During the desperation of the twilight gap battle, the vanguards' most powerful guardians were summoned to defend the entrance to one of the last remaining civilian evacuation zones. For 120 hours the golden age's most valiant guardians fought and died as they attempted to hold off the overwhelming siege. Recognizing the "grim reality" of this ill fated battle an order of hunters refused to fight and under the command of Cayde-6 disobeyed the vanguard's orders and retreated into the city of illuminatum where they aided the citizens in their exodus to the last city. Upon the the successful evacuation of humanity's last large scale civilian population the hunters took up defensive positions. When the forces of darkness inevitably overcame the remaining guardians on the front lines and pushed through the twilight gap into the city they met these same hunters. Here they halted the darkness and survived for six days waging an apache resistance against the legions of hive, vex, and fallen who'd come to collect Earth's greatest resource. In an attempt to buy the people time and to honor the sacrifice of their lost comrades these hunters fought without mercy, and without remorse. Seeking out their enemies and systematically destroying them. On the seventh day the legions of darkness were forced to retreat. It's because of Cayde-6 and what would later become referred to as "the Wolfpack" that the grief and horror of the twilight gap wasn't the end of humanity. That's why hunters have Gjallarhorns and that's why Gjallarhorns have "Wolfpack" rounds young guardian.