I couldn't finish 'em. Looks like this's gonna get complicated.
Airy is a boss in Bravely Default, fought in three forms.
From Chapter 5 onwards, triggering the breaking of a Crystal leads to the "Finale" chapter and a fixed boss battle where Airy will defeat the party. She then becomes the final boss found within the Dark Aurora and is fought in two forms. In the "The End" chapter, her first two forms are fought aboard Grandship, leaving her third form to be fought within the Dark Aurora.
The third form is more revealing in the Japanese version.
Even at levels as high as 70 or 80, Airy can be difficult if ill-prepared for she uses attacks that can inflict massive damage and hinder the party.
First form Edit
Airy's hideous larva-like form uses Slaughter, an attack with her countless limbs that has slain countless Warriors of Light.
Airy resorts mainly to physical attacks. She tends to start with Tight Bind, inflicting Stop on the party, and then usually follows with Slaughter, a powerful physical attack on the whole party that also inflicts poison, but costs her 1 BP to use. If the party is poisoned, she can use Poison Punisher, which can deal lethal damage to the poisoned party members. As she suffers damage she uses Spike Guard, countering all physical attacks with a normal attack of her own, and remove it a couple of turns later.
At around 15,000 HP, she transforms into her second form.
Second form Edit
Airy's odious, pupa-like form uses powerful attack magic along with acedia, which has a dispel effect on all her foes and leaves them vulnerable to all elements.
Airy uses strong elemental magic attacks that affect the whole party. Eventually every 3 or 4 turns, she uses Acedia to remove the party's buffs and give them a weakness to all elements, which she exploits for massive damage if not undone. She can mix in Luxuria, which casts Charm on the whole party. She can also cast Berserk on a party member (although this is merely annoying at best). After losing half of her HP once, she heals to full HP.
Third form Edit
Airy's final form uses the ultimate fire attack magic Zeta Flare to incinerate her foes and the deadly Plague ability to instantly slay those with status ailments.
Airy uses attacks from both previous forms but incorporates new attacks with Zeta Flare, a major fire-elemental attack, as her only damaging spell. She also uses Dark Abyss, which inflicts Dread on the party, and Plague, which kills all party members if they have a status ailment. Airy Defaults before using Acedia and then follows with Zeta Flare, giving the party no time to react in-between moves, dealing around 5,000 damage if not protected. Airy uses Recover twice, after losing half her HP each time.
The best method to counter Airy's arsenal of attacks without using too many ability and equipment slots is to bring a high level Spiritmaster who can render most of Airy's attacks useless by providing status and elemental protection. A healer is still recommended. For offensive purposes, either a Ranger and/or Spell Fencer can deal large amounts of damage to Airy, exploiting her Bug nature and weakness to Fire.
A Dark Knight can also work if one uses a Dark/Black Bane and Minus Strike, provided protection and timely healing are always available. Since Airy can debuff the party, a party member with the Piracy command is a good idea to keep her stats on check. A Performer can also complement the Pirate's approach to hinder Airy further.
When facing her third form, it is recommended to bring Fire-elemental resistance for Zeta Flare. The Aegis Shields found in Dark Aurora and Dimension's Hasp can be useful to prevent Dread; Dark Aurora also contains the fourth and final Safety Ring, which can be equipped to prevent instant death; in any case, the Spiritmaster is still as helpful as before, and a Black Mage can assist with the Abate Fire ability.
Alternatively, an Arcanist with Status Ailment Amp and Black Magic can simply cast Sleep on Airy each turn, wasting her turn while the rest of the party attacks her; this makes it possible to win the battle without Airy getting to act.