Skolas, leader of house wolves, self proclaimed kell of kells. Battle of twilight gap he was somehow prevented from being at with all the other fallen by Mara Sov as per Petra. However, the silent fang remained on the loose, and evidently got their hands on powerful technology to be able to get Skolas away from the nine, beings who are supposedly very powerful. Additionally, lore says the vault of glass technology existed at any point in time, but only in the geographic area of the vault. Skolas was somehow able to remove the time warping platform tech from the vault. Evidently he has some unknown power. Therefore, how was Mara Sov able to stop him from being in the battle of twilight gap. We don't know. Anyways, I digress. Silent fang could have scavenged the battlefield easily after Twilight Gap.

The Fang did not rescue Skolas from the Nine, the Nine released him. And what purpose would scavenging the battlefield for Guardian armor to construct a Guardian weapon have? If the Fang made it, it would be a lot more Fallen-like. The perk would also then have the insignia for the HoW, not the insignia for the Iron Banner

Then what's the comment your ghost makes asking how the fang could have got Skolas from the nine. And I'll admit you obviously know more lore than me, so I'll trust you on these

The grimoire confirms that the Fang had nothing to do with Skolas's freedom. The Nine released him

I'll find the link tomorrow. It's late. Is it possibly the stranger,though

And another thing: Gjallarhorn was never accidentally added to a loot table. It was announced and showcased and hyped for a good while leading up to the release of vanilla Destiny. Hell, it was even in the live-action trailer