Donny at Ivald's Ruin in the Howling Fjord wants you to kill 10 Iron Rune Destroyers, 5 Iron Rune Laborers and 2 Iron Rune Sages.
Keep it down, <race>. These iron dwarves are quick on the trigger. Now don't let the activities down in the dig fool you. Those steel-skinned abominations aren't digging anything up! No sir - on the contrary - they're burying the site! For whatever whacked out reason, they don't want anyone finding this place.
What kind of dwarf buries ancient relics and dig sites? I'll tell you what kind: the kind you kill with reckless abandon! Get in there and take 'em out!