Recommended: Bring a Selbina Clay as you'll find the stone monument along the way. Sneak and Invisible are critical. Also, bring at least one friend to help with opening gates in Eldieme Necropolis. A level 60 RDM can easily solo the NM Ahtu that must be killed.

Head to The Eldieme Necropolis through (I-10) of Battalia Downs. Head to (H-9) and take the south door and go to (G-9). If the south door is not open or if can't even get into the room with four doors at (H-9), have a friend go to (H-8) and push the plate there. Run into one of the graves in the middle to fall down. Check your map, then travel east. When you change maps, head to (J-10) and zone.

You will be back in Batallia Downs, with Ahtu in front a distance away from you. Buff up, then kill it. It will drop an Engraved Key. You may also want to search around for the Stone Monument as well. Head back to North San d'Oria and trade the key to Vamorcote for a cutscene and your reward.