Story
Fortunately, Skarm, the Fang Legionnaire, was still conscious. He told you he lost contact with his comrades after they headed for the Dranactus Underkeep, and that there was a device in the Watchtower Camp that controls the surveillance facilities in the area. Investigate the tent he told you about.
After completion (spoilers)
"Reuben! That's the guy Hystan mentioned. The surviving Destruction Archon!" Fortunately, Skarm, the Fang Legionnaire you found in the North Laborer's Tent, was still conscious. He told you he lost contact with his comrades after they headed for the Dranactus Underkeep, and that there was a device in the Watchtower Camp that controls the surveillance facilities in the area. You headed straight to the Watchtower Camp with Nemon, where you destroyed the central surveillance unit and neutralized the Watchtower. You then searched the camp and found the Underkeep register, where you found the names of Reuben and Fang legionnaire Kanir. It had become clear that the last Destruction Archon survivor was held in the Underkeep. You decided to head to the Hidden Cave to find the Fang Legion survivors and get more information about the Underkeep.