Rift Quest:Among the Endless  

All the Shatterbone cultists except the Sentries have a chance to drop the Cultist Uniform Pieces. Once you have enough, use them to become disguised. Now, quickly, go talk to High Justicar Vigman before it wears off. You want to get close to him before you use it. After, get away from the wandering Shatterbones before the disguise wears off!