Tattered Frostwolf Shroud

The Tattered Frostwolf Shroud can drop from any mob in for leatherworkers, but most likely from Dorogg the Ruthless for the quest The Butcher of Bladespire at Bladespire Citadel. It starts A Warrior's Shroud, which begins a short chain to unlock the Tannery blueprints for the Garrison.