Gangue Shade Relic
The Gangue Shade Relic is a stone relic in the last corner room of the Dead Trenches (in Orzammar). Within the room you fight shades of Dead Legion and will find a single relic shaped like a headstone. The relic is clickable but nothing happens unless the character clicking the relic is wearing Legion of the Dead Armor. If you are wearing the complete set of armor (helm, gloves, armor, boots) a Gangue Shade will appear and attack you.
The Gangue Shade is not hard to defeat at higher levels (level 16+) but drops nothing when killed. There appears to be no quest starting from, or ending with the Shade.