The cryst-fairies are humanoid, fairy-like creatures that appear in Bravely Default and Bravely Second: End Layer. According to the Crystal Orthodoxy, the cryst-fairies are supposed to be the tenders of the Crystals. The cryst-fairies also have the ability to become human-sized fiends when they see a need to fight.
According to the Orthodoxy's teachings, the cryst-fairies are helpers of vestals in their responsibility to tend to the crystals. The cryst-fairies always ensure that the vestals and even other Crystalists pray to the Crystals and uphold the faith. Despite what Orthodoxy promoted, though they value the crystals, the cryst-fairies seen so far are not the benevolent beings they were presented by the religion to be.
The Cryst-fairies are eventually revealed to be creation of godly beings that carry out their creator's will: Anne created by Providence to ravage Luxendarc with Ba'als while her younger sister Airy was created by Ouroboros to enact his desire to invade the Celestial Realm. Compared to her sister as Fort-Lune intercepted any Ba'als she sent to Luxendarc, Airy managed to nearly reach her quota by traveling through the multiverse while using the Orthodoxy's teachings to deceive versions of Agnès Oblige to assist her in having the Crystals' powers go out of control. Such an event will produce the emergence of the Holy Pillar, which Airy exploits to weave together Luxendarc and its parallel counterparts until Ouroboros obtains his portal to the Celestial Realm.
But Airy's foiled when one version of Agnès learned too late of the deception and watched her comrades Tiz Arrior and Edea Lee killed. That Agnès, wounded and using pendant to warn other versions of herself of the "evil one", ended up in a version of Luxendarc in its past. Found by Sage Yulyana and Lester DeRosso, assuming her to be an Angel, Agnès told them the events to come in her timeline as they and other versions of themselves act to plan a means to stop Ouroboros if they cannot prevent his coming.
At the same time Airy was five worlds close to her goal, Anne indirectly supported Tiz Arrior as Agnès's protector through the will of the being who guided the wind vestal's group. But once Ouroboros is defeated, Anne begins the next phase of her own plan when she recruits Kaiser Oblivion on the false impression that she is helping him so she can displace the moon in order for the Ba'als to attack Luxendarc at full strength and unopposed. But when that failed, Anne learned of the Great Chasm her sister created and uses it to forge a direct link between Luxendarc and the Celestial Realm so that Providence himself and manifest.
"Cryst" referring to both the words "Crystal" and "Chrysalis", the latter in relation to their butterfly-themed wings and fighting forms.
fairy is a type of mythical being or legendary creature, a form of spirit, often described as metaphysical, supernatural, or preternatural.A