Look for a scourge hex area called “the black well” and win the battle. The game is randomized but mine showed up as a level 6 encounter in the “Frost Adventure” campaign. The battle is against the royal drill (skeleton bard) and two “backup band” bard skeletons. The droll had 12 physical and magic armor while the others had 6 magic armor on one and 6 physical on the other.