I recently returned to the game and found out about these achievements and started working on them. However I made it to this one and am at a loss how to do it. Ive looked all over the internet, re-read everything in game, and have no clue what Im supposed to do for the "Undeterrable Wayfaree" part of it. Any help would be appreciated. Thanks!
In the final group fight before the specter of rage activates, note the model used for the following: equip your epic, turn your back to prevent riposte kills, when the specter changes forms hit it with the appropriate skill.