This quest is next in line after Maker’s End in the quest chain. Head for the Grave-Hoard, which is far to the North of Nora lands. When you get there, be careful for a bandit camp at the entrance, then climb up and into the entrance proper. There you’ll find a bunch of datapoints to scan. When ready, follow your waypoint through the door into the next rooms. Be careful a couple of Eclipse and a corrupted Watcher will drop in on you here. Take them out then keep going until you find a locked door. Scan it with your Focus to find that you’ll need to restore power.
Head into a nearby room to find the three sets of breakers you’ll need to fix with a simple puzzle to open the door. There’s one on the upper level, then two below. The solutions are as follows, with everything reading left to right:
Upper floor - Up, Down, Left, Right
Lower floor with broken directions box - Up, Right, Left, Down
Other lower floor - Up, Up, Down, Down
When you’ve got these three sorted, head back up to the door and go through now that it’s unlocked; make sure to grab the Powercell on the left as you enter. In the next room there’s a few Eclipse and a Corrupted Ravager. By now you should be getting pretty good at taking out these guys, so kill them all however you want then follow your waypoint into the cave beyond.
Follow your waypoint through the cave then up the debris into the next section of the area. Make sure you grab all the Datapoints in the library room, then head through to the breifing room. Loot everything you want and get all the datapoints, then when ready activate the holoprojector to get another window into the story.
Once that’s done, head through the corridor and then out the door to get a short cutscene which will reveal to you a fully functional Deathbringer that you’ll need to fight, as well as a bunch of Eclipse. Now, as tempting as it is to start the fight from the walkway, don’t. The Deathbringer can bring down the walkway, with you on it. So before you engage, head around one of the sides and drop down onto the ground. First things first, try to take out the snipers around the area, then it’s Deathbringer time.
Deathbringers have a lot of health, and are heavily armed and armoured. Their one big problem is mobility, so keep moving. Also, they can destroy cover, so again, keep moving. Use your most damaging weapon to hit the weakpoints until it decided to do a swarm missile attack, at which point it will expose weakpoints on its knees. Hit these and you’ll knock it over and expose the heatsinks which you can hit for major damage.
Once it goes down, mop up any Eclipse then go through the door towards your waypoint. There are a few more datapoints here to pick up, then go into the War Room and activate the holoprojector again. When it finishes, head up the escape lift and talk to Sylense then that’s this quest over. All that’s left is to zipline down the Horus’ arms.