Threadbare Weighted Tabard - TBL Evolving Item
Threadbare Weighted Tabard are one of five different evolving items in TBL that drop in the Fight Fire With Fire mission. All of these items can be evolved by completing a bunch of older achievements and will result in some of the most over powered items this game has ever seen.
In order to evolve the Threadbare Weighted Tabard to level 2 you need to complete all of the collectibles achievements from Call of the Forsaken - Ring of Scale.
Achievements Required for Rank 2:
After the item is evolved to level 2, you'll be able to grind enemies in order to level it most of the way to the final rank, Tabard of the Guardian. From what I understand so far, ranks 3 and 4 both are earned by grinding EXP. In order to level it to the final rank and acquire the Tabard of the Guardian you'll need to complete the Master of The Burning Lands Achievement which basically requires you to complete all of the TBL expansion except for the raids and collections.
Other TBL Evolving Items Guides: