Horizon Forbidden West: How to complete the Valley of the Fallen side quest

Nakko has requested that you go check on his brother, who has decided to attempt the old challenge near the Valley of the Fallen. This mission will most likely be discovered after you've completed the primary quests The Kulrut and the Cradle of Echoes. Defeat the valley's machines and shield anyone caught in the crossfire. In Horizon Forbidden West, here's how to finish the Valley of the Fallen side mission.

Follow the path south after receiving the quest from Nakko in the arena to meet up with Ivvira. She'll be on a stage with a wounded warrior. You'll have to go ahead and do it. Follow the path put out in front of you to complete the trial. If necessary, use your Focus to locate the climbing route.

Follow the trail to the top of the trial and inspect the dead machines and soldiers along the way. You'll have two missions: visit the waterfall and travel south of the Horus. First, go to the waterfall. You'll have to cope with two machines near the waterfall: a Scorcher and a Longleg. Go to the top of the waterfall and override the machine lure once you've killed both machines.

Go south of the Horus to the area south of the Horus. Once there, you'll be confronted with a vexing combination of machines: a Tremortusk and a Thunderjaw. If you manage to knock the weapons off the Thunderjaw, save them for the Tremortusk to help drain its health. Override the lure that is against the cliffs after the fight.

You'll discover there's a third lure after you've overridden the first. To get to the region where the third lure is located, go to the left of the second lure and climb the mountain. You'll have to kill a few more machines once you've arrived at the area. Fortunately, there are only a couple of Spikesnouts this round. Overcome the seduction and speak with the Tenakth survivor. Some Spectres will materialize after a brief cutscene. After the Spectres have vanished, speak with Ivvira to finish the task.