Story
The documents found in Reuben's Hideout mentioned the fortress where the High Priest had last been and Archon scripture. Nemon speculated the fortress may lead you closer to the Core. Find out the location of the fortress from the graverobbers in Basfelt Ruins.
After completion (spoilers)
"This must be the location marked on the map." The documents found in Reuben's Hideout mentioned the fortress where the High Priest had last been and Archon scripture. Nemon speculated the fortress may lead you closer to the Core. You gathered information about the fortress and scripture from the graverobbers in Basfelt Ruins. In the Abandoned Ruins, you found Archon scripture, though it was torn. There were further records concerning a fierce war, the Underground Fortress, and the Blood Sword. Nemon was convinced that the Blood Monument would be the key to unlocking the Underground Fortress.