The nest is divided into five main parts. When the section's boss is killed, a treasure chest will appear that drops the Giant Faceworm Skin.
Once you are inside the instance, go south and talk to Chaos and Iris. Faceworms will appear (alongside with other monsters that can be ignored).
Kill all Faceworms. A Dark Faceworm will spawn at the south-east part of the map. The Faceworm Eggs around it regularly cast Heal on it thus it's advised to eliminate them.
After eliminating the Dark Faceworm, a Treasure Chest will appear containing a Giant Faceworm Skin and the party can proceed.
Talk to Iris and Chaos again. Faceworms spawn again. Mounds appear around the map spawning Faceworm Larvas on touch. They can be skipped. The same boss fight occurs as in the previous section. A new portal opens up in the south.
Poison traps appear everywhere, try to kill them as soon as possible because several sacks can deal fatal damage. Proceed to the north and kill all Faceworms.
This Dark Faceworm has no healing eggs but damaging poison traps. Kill the boss again.
At the next section, another kind of traps, poison clouds are present. These ones are stronger than the previous one thus it's advised to avoid them or spam Kyrie Eleison to lower the damage.
The 4th boss fight will now combine healing eggs and poison clouds. Defeat the boss once again.
Talk to Iris and Chaos again. After that, the Faceworm Queen will spawn.
The Queen's HP varies (28m + (2m * party member)). Her noteable spells are Earthquake, Stormgust and Waterball and she changes her element to either Fire, Water, Wind or Earth.
When she does it, an announcement is made. All three adds (healing eggs, poison traps and poison clouds) aid her in battle.
Defeating the Faceworm Queen the fifth treasure box appears that contains two Giant Faceworm Skins.
Monsters
Note that Faceworm Queen's HP increases with more people in the party, and she changes her element during the battle.
