You’ll get this one as you head for the Carja Border Fort in the main mission. On the road you’ll come across a series of carts that have been overturned, as well as a bunch of dead machines. Speak to Marzavid to start things off. Once the conversation is over, you’ll get to face - probably - your first Longleg. This large, bird like machine is fast and very aggressive, with a ranged sonic blast attack, as well as a long range leaping attack. It will arrive with a bunch of Watchers and Scrappers as well, but the Longleg is your main enemy.
Hit its sides with Tearblast arrows to rip off the jumpjets it uses to perform leaping attacks and you’ll vastly reduce its maneuverability. Once they’re off, use your tripcaster to either blast or shock it and then take advantage of that to get further damage. Once it’s down, mop up the Watchers then speak to Marzavid again. He’ll tell you to find Dirid, so use your Focus to find his tracks and follow him. When you find him, talk to him, and then get ready for a fight with another new enemy, the Stalker.
This is a tricky enemy to fight. It can hit you with a ranged attack, go invisible, drops mines if you get too close and its melee attack is devastating. So how the hell are you supposed to fight it? Well, it’s back to the Tearblast arrows. Use them to rip off the various components that allow it to perform most of its attacks and it’ll shift to just trying to leap on you. Once that happens, use your tripcaster to set wires between you and it, and be ready to dodge, a lot. It will leap over the wires, but just keep setting them up until you’re surrounded with traps, it’ll land on one eventually and when it does, take that moment to hit it.
Talk to Dirid, then head back to the caravan and talk to Marzavid to complete the quest.