The hidden Frost Death Knight Artifact skin is available on live servers this week! Go get it before it’s gone!
Runes of the Darkening unlocks the Dark Runeblade appearance for the Blades of the Fallen Prince Frost Death Knight Artifact weapon.
Image courtesy of Reddit user Norumu (Source)
The appearance is a guaranteed drop from The Soultakers world boss trio located in Stormheim (79, 8). You can easily solo this.
Legion world bosses are on a fixed rotation, so it will take 10 more weeks before this one is available again. You have until Tuesday in the US region or Wednesday in the EU region to get it.
The appearance also has a small chance to also drop from Icecrown Citadel bosses as well.
Source: Reddit