For those who have completed the Shadowbringers expansion, the concept of immortal and blue-and-orange morality faeries is not new to the world of Final Fantasy XIV.

The lore behind Ahleh Oohrs, Badkhaneh, Dran Myhk, and Fohl Lye draws heavily from the themes introduced in Il Mheg of the First. It also draws on the lore from the alliance raids for Ivalice in Stormblood, specifically on the topic of the Ultima Seraph, and therefore also from the raid series introduced in Endwalker.

Additionally, the collective information on the history and biology of dragons on Hydaelyn has been a significant part of the lore creation process and its main source of inspiration.

If you are unfamiliar with these concepts, we recommend setting this article aside and continuing your adventure through the wonderful world of Final Fantasy XIV.

For the full entry, see Hospitality Laws

Amidst the Third Astral Era — new, bold and lawless — the Courts have found conflict between one another, clashing as fire and water, wind and earth.

First among the draconian paragons to take action, Nidhogg roared for order.

From that roar, a council of immortals has welded the laws of hospitality.

There are no formal rites for a fae to migrate from one Court to another. However, all fae are dependant in one way or another on their Land. As each Land has an aetheric composition it is more aspected towards, there will be major changes and adaptations a fae will have to undertake. The degree and complexity depends on the individual fae and the Court they are migrating from and to.

For Badkhaneh, there is a considerable risk of a loss of immortality or life and the process shall be torturous, as their aether monolithic between the three essences of soul, memory and body. Changing Courts as Badkhaneh might result in memory loss, fall from immortality, damage to the soul, decline of strength and death.

Elemental Interactions

Winter

Winter Court is heavily aspected towards Astral Ice. The Nativities, Conquests and Submissions of the migration are as follows:

• Fire aspected fae, especially Summer Court, will face hardships and impossible suffering.
  Astral Fire possesses more risk of imbalance, stagnation and death than Umbral Fire;
• Earth aspected fae, especially Autumn Court, will face little trouble and their path shall feel natural.
  Astral Earth will face more delays and stagnancy than Umbral Earth;
• Wind aspected fae, especially Spring Court, will be obstructed and shall decline in power significantly.
  Astral Wind will make no progress, where Umbral Wind may persevere through suffering.

Autumn

wip

Summer

Winter

wip

Spring

wip

Essence Changes

Each Court has natural processes they are most attuned to, as well as abilities that their nature grants them. A fae changing from one court to another will gradually lose the essence of their prior court as the Land nourishes and necessitates change.

Winter

• An ability to perceive the souls of the dead and guide them to afterlife.

Autumn

wip. mushroom?

Summer

wip

Spring

wip

The fae born of blessing of the dragonkin share in their ability to imbue their speech and roars with aether. As their nature is both more ephemeral and volatile than that of their dragon patrons, promises and oaths bear a natural weight for the fair folk.

Q: Also a broad question but. If a Promise is made with a fae, and the other party breaks said promise, what is the extent and nature of the action the fae is Legally allowed to take in response? In the hypothetical, the terms of the promise made do not specify consequence should said promise be broken. Does this lack of specificity mean the consequence, then, is whatever the fae deems fair, assuming it’s settled outside of court?

A: Beaking a promise as a non-fae doesn't have as much consequence on the oath-breaker as it would on a fae, as the extent they bind themselves to it is not the same as it is for fair folk, whose words are their magic and their magic - their essence. So the party breaking the oath would not suffer damage and, well, debuff. But fae to whom the oath was broken will feel it, like a snapping thread. 
It might give some small power over the oath breaker on a metaphysical level? On a sliding scale, severe especially if the degree of the oath was closer to DnD warlock pact. Angry patrons are life-threatening, power-stripping business.
Honestly, out in the open unclaimed wilderness, Hospitality Laws are not in effect, so the benevolence or malevolence of a fae is up to the fae's mood and personality. If they elect to go batshit over the slight of the broken oath and maul the offender, none would judge them.