Order & DestroEdit
Kill Graw Leadgut, 29 champion, in Bloodmaw Cave in the Badlands. Loot Tarnished Medal from his body and right click it in your inventory, after right click the item disappears and you receive the unlock.
Only one Tarnished Medal drops, so if doing it with a party you'll have to kill him multiple times for everyone to get the unlock. Cave entrance 59597,26829.
Warning: Graw has the Cleave in Two ability, which when it lands hits you for a flat 50% of your total HP (regardless of your level, gear, etc.). Meaning, even a decked-out level 40 can get dropped by this guy. Being a champion and an ogre, he's got decent HPs/AF/toughness, so even though his regular melee won't hit you for much, he can take a beating from you even being a level level 29 mob. Bring a healer friend, or kite if you have decent ranged damage.