With help from Garlond Ironworks, you reach the lair of the dread wyrm Nidhogg.
How to Unlock
The Aery 4-player dungeon is unlocked by the level 55 Main Scenario Quest Into the Aery.
Clear the Aery Exterior
Players will periodically be targeted with small circle attack markers of Levinbolt. Defeat the enemies you encounter to open the barriers to the next areas. Keep an eye on the map to avoid going into a dead end.
The tank should keep Rangda facing away from the rest of the party to prevent them from being hit with Electric Predation.
All players should stay near the center of the room to avoid the donut attack, Electric Cachexia, that periodically hits all but a small area around the boss.
Rangda will sometimes knock back all players with Electrocution, so be sure to go back near the boss to avoid the donut attack.
Kill the Leyak enemies that sometimes that appear. Their Reflux attack inflicts Heavy on players hit by it.
Rangda will sometimes cast Ionospheric charge, which creates a tether between one player and the boss, while targeting other players with one or more circle attacks in a row. Non-tethered players should move out of the way of the circle attacks, and the player who is tethered to the boss should touch one of the statues around the edge to transfer the tether to it. If they do not, they will take damage and be inflicted with Paralysis. If the tethered player does not go to a statue, another player can walk between the boss and the tethered player to transfer the tether to them, and then go to a statue to prevent the attack.
Clear the Aery Interior
Go southwest from Rangda's area to go down below. When your path is blocked, kill the Smoldering Dragon to open the way.
The boss sometimes uses Proximity Pyre, a circle attack centered on the boss.
When the boss first casts Inflammable Fumes, an unsafe ring will appear around the area. Be sure not to step in this area.
Whenever the boss casts Inflammable Fumes, there will be circles of fume spinning around the boss, which can be safely stepped in at first. The boss will then cast either Ashen Ouroboros, a donut attack around the edge of the room, or Proximity Pyre, a circle attack centered on the boss. The fume circles will explode at the same time as the donut or circle attack, so find a safe place where you are not in the circles of fume and not in the other attack marker.
Crippling Blow is a high-damage attack on the player highest on the enmity list.
Deafening Blow damages all players.
Body Slam knocks all players back from the center of the area. Make sure to stand near the center to avoid being knocked back into the unsafe ring around the area, or use a knockback prevention move such as Arm's Length, Surecast, etc.
Clear Errn Scorh
Kill the enemies up ahead to make pillars fall. Go across the pillars to the next areas.
Nidhogg periodically uses Deafening Bellow, which hits all players.
Hot Tail is a line attack across the length of the area in the direction that Nidhogg is facing.
Hot Wing is two line attacks on each side of the area under Nidhogg's wings.
Hot Tail and Hot Wing are sometimes accompanied by eyeball-shaped circle markers under random players. Move out of these circles to avoid taking damage from them.
Players will sometimes be targeted with circle markers that follow the players. Make sure not to overlap other players with your circle.
Cauterize is a fiery line attack across the length of the platform. Move out of the attack to avoid damage.
Nidhogg will sometimes make a random player float upward and then be held in place by The Sable Price. The Sable Price will then cast Sable Weave. The other players should attack the Sable Price until it is destroyed. If The Sable Price is not destroyed before it finishes casting Sable Weave, the trapped player will die.
Nidhogg may sometimes target the player highest on the enmity list with a high-damage attack.
Nidhogg will eventually become untargetable and summon several enemies, including Ahleh, who sometimes targets a random player with Roast, a line attack. Nidhogg's Rancor gauge will fill while these enemies are present, so defeat them quickly to stop the gauge from filling. When all of these enemies are defeated, Nidhogg will cast Massacre, damaging all players. The strength of this attack is determined by how much the Rancor gauge filled before the enemies were defeated.
At this point, in addition to the attacks that you have seen thus far, Nidhogg may sometimes cast Horrid Blaze, targeting a random player with a stack marker. Other player should stack together with the marked player to share the damage.
Completing the Quest
Defeating the boss will complete one of the quest objectives for the Main Scenario Quest Into the Aery.