How to complete The Broken Sky main quest in Horizon Forbidden West

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You’ll start The Broken Sky immediately after leaving GAIA if you choose to pursue the Aether AI first. This quest has the lowest level requirement of all the subordinate AI quests, but it’s also one of the lengthiest in Horizon Forbidden West. This guide explains how to complete the quest, including some tips for defeating the mammoth of a boss.

As you’d expect, this quest isn’t as simple as it might seem. The coordinates for Aether are the stronghold of one of the Tenakth tribes. When Aloy arrives, she’s surprised to hear that she’s expected. Follow Dekka through the museum and watch the holograms along the way if you want. You need to visit the tribe’s leader, who will tell Aloy that she can enter the room beneath his throne, where Aether is kept, if she helps him.

Follow the quest marker to meet one of the last living Marshals. He’s been tasked with taking Aloy to a stronghold where a tribe’s leader has refused to send his warriors to a ceremony. Once you meet him, you’ll need to follow him along the road to the stronghold, a huge walled-in village. You’ll need to fight a few rebels along the way, or you can sneak past them if you’d prefer. Once you arrive, the leader sends you away. He won’t send his warriors while the wall he’s behind stands.

This gives Aloy an idea, and a new step in the quest appears. You need to head out of the village to a specific spot where you can look at the Bulwark. Scan it to find a tank, a potential weakness. You’ll need to climb up and into the wall by ascending the waterfall to your left and breaking in through a cavity. Inside, Aloy finds that she could destroy the wall with the right equipment.