Talk to Den in Mother’s Crown to start this errand. He’ll ask for your help in finding his friends that went missing in the ruins of Devil’s Thirst.
Head to the marked location just north of the Devil’s Thirst Tallneck. Activate your Focus then locate the corrupted watcher remains. After finding it, examine it up close to update your objective. Next, use your Focus again to find the tracks. Highlight it and follow it until you reach a ruined building with two Sawtooths patrolling inside.
The braves have taken refuge on the higher ground but unable to leave because of the two machines. If you have the ability to override the sawtooths, you can sneak and take over one of them and make them fight each other. Alternatively, if you have fire or blast wires for your tripcaster, you can put them by the ruin doorways where the sawtooths can exit. At this point, sawtooths are probably still dangerous so make sure to have your fire arrows ready just in case.
After defeating the sawtooths, go inside the ruins and examine the supply crate to trigger a cutscene. Report to Den to complete the quest.
Video Walkthrough