Vile Perversions (WAR History and Lore)  

For this unlock, you must make your way through the Mistwood Grove Public Quest to the very edge of the peninsula of land in the center of the map. Around 33k/27k there is a Defiled Body lying just outside of one of the Dreadtalon Guardian nests.

Interacting with the body will grant you the unlock.

NOTE: IF (like me) you're led here from the "Vile Perversions" H&L entry in Ellyrion, it's the shackled prisoner at about 51x59

History & Lore in The Blighted Isle