This page explains how to complete the level 89 Endwalker duty, The Aitiascope.
How to Unlock
The Aitiascope, a 4-player dungeon, is unlocked by the level 89 Main Scenario Quest Her Children, One and All.
On the Way to the Central Observatory
On the way to the first boss, you will eventually encounter a certain enemy that eventually spawns four Sinking Arrogance enemies. Once the Sinking Arrogance enemies appear, you can focus all attacks on them and ignore the enemy that summoned them.
Frustration damages all players.
Aglaea Bite is a high-damage attack on the player highest in the enmity list.
Aglaea Climb causes two of the boss's appendages to glow. There will be a cone attack under each of the glowing appendages that affects that entire quadrant of the area. Stay under one of the non-glowing appendages to avoid the attack. The boss goes to the center before performing this attack, so you can use the ridges on the floor to help identify the safe quadrants. The boss sometimes performs the same attack again, hitting the opposite quadrants from the first attack.
Aglaea Shot places line markers from the center to the edge, then the bullets will continue to float above the edges. The same attack will occur again, but this time line attack markers only appear briefly just before the attack occurs, so to avoid the second attack, be sure to stay where you were when avoiding the first attack.
Odi et Amo targets two random players with a large circle attack marker. Move away from the circle attack marker, then a random player will be targeted with a stack marker. Unmarked players should stack together with the marked player to reduce the damage of the attack.
Disparagement targets a random player with a large cone attack from the front of the boss.
On the Way to Saltcrystal Strings
On the way to the second boss, there will be golden flames in some areas. These flames may take action to help you. Stay within any blue markers that these glowing flames create.
Tartarean Impact damages all players.
Tartarean Spark targets a random player with a line marker.
Vexillatio places large line markers on the west and east side of the area. The affected areas will be raised up and become inaccessible. Afterward, there will be four niches in the walls, each with crystals that the boss tethers to. The boss will cast Shield Skewer, covering the narrow area with a line attack. Watch the health bars of the tethered crystals to see which ones are being drained more quickly; they will be destroyed first, giving you a safe niche to hide in to avoid the Shield Skewer line attack. After the line attack occurs, the walls will shatter, restoring the area to its original size.
Anvil of Tartarus is a high-damage attack on the player highest in the enmity list.
Shrapnel Shell places moving target circles on the floor that will move diagonally outward from the boss toward opposite corners of the area. Players should avoid the corners that the circles moved to, instead staying in one of the corners that the circles did not move to. The attack will place a large number of circle attack markers along the lines that the target circles traveled.
After this, Vexillatio will be paired with Shrapnel Shell. The tethered crystals will be drained, but one side of the area will be hit with Shrapnel Shell, so make sure to find the quickly-draining crystal that is NOT on the same side as the target circle indicators of Shrapnel Shell.
Amon, the Undying
The boss will be in a fixed position throughout the battle. Attacks that normally do more damage when performed from a certain position will not have a damage bonus during this battle and can be performed from any direction.
Dark Forte is a high-damage attack on the player highest in the enmity list.
Thundaga Forte places a proximity attack marker in the center of the area. Move to an edge of the area to reduce the damage. Afterward, lightning cones appear on the ground originating from the center. Some cones will have fast-moving lightning and some will be slow. Stand on one of the slow cones until a neighboring fast cone has disappeared, then move to where the fast cone was.
Strophe places a large floating disc in the area. Antistrophe will make the disc rotate until it is vertical to the ground. It will perform line attacks outward from both faces of the disc. The line markers only appear briefly, just before the attack hits. Be sure to watch which way the disc is rotating and avoid standing in the path of either of its faces.
The boss will sometimes cast Right Firaga Forte or Left Firaga Forte. This attack will hit the entire half of the area indicated by the name of the attack, with "right" referring to the boss's right and "left" referring to the boss's left. In other words, to avoid Right Firaga Forte, stay on the right side relative to the way that you are facing, and to avoid Left Firaga Forte, stay on the left side relative to the way that you are facing.
Entr'acte damages all players.
When the boss is casting Curtain Call, random players will be targeted with large circle attack markers. Curtain Call will attack the entire area and deal fatal damage to anyone hit, but before the boss finishes casting it, a circle attack marker will appear in the center of the area, and an obstacle will appear there. Hide behind this obstacle to avoid the Curtain Call attack.
At this point, Strophe will create two discs instead of one. Both discs will perform line attacks, so make sure that you are not in the path of either of the two discs.
Completing the Quest
Defeating the boss will complete one of the quest objectives for the Main Scenario Quest Her Children, One and All.