Leave the alley and head south out of Memory Square. You’re going “clockwise” around the edge of Xion – at least, that’s the idea – so the next terminal should be on the left. It’s on a wall opposite the entrance to Exile’s Passage, and it displays the Greek letter μ (mu).

The Lost Ark puzzle is triggered after speaking to Mann, who can be found in the Presence Chamber after completing main objectives in Altess Levoire.

While inside, it’s crucial to gather every collectible, as Angels won’t get a second chance to enter Altess Levoire later. Additionally, Eve won’t be able to scan the surroundings inside, so it will be twice as hard to find everything.

The Stellar Blade Lost Ark puzzle is part of one of the many side quests that you can indulge in during your time in Eidos 7.

The day one patch for Stellar Blade adds a New Game Plus mode, and it's possible to go ahead and check out what all will carry over to a NG+ run.