Vhig Prime being referred to as male is a slip-up on my part. I do occasionally use the wrong gender pronoun in my homebrew work. And again, thank you for the comments and criticism.
Hmm... how about this?
Mayhaps it's just me, but I feel like aloof and arrogant are rather cliche traits for races that are advanced, air-related, and especially arcane-magic-saavy. I like how you use alliteration (sp?) at the beginning of that section (further proof of your skilled writing style), but I feel like mixing up the content and rewording it a bit might come across with a slightly more original feel for their personalities.
Personality: Aloof, arrogant, and accomplished. This does not render them uncaring, or without kindness, however; for the most part, the Alarcrayin have a genial, matronly condescension towards others that they consider lesser. They can become extremely overbearing in the presence of groups which they truly dislike, but most Alarcrayin make an honest effort to be nice - at least to someone's face. Culturally, this is not considered duplicitous; they have advanced social rules regarding the dual nature of social and private life.
The Alarcrayin - and thus Alarus - have mastered the integration of magic into ordinary society more than any other family. Alarcrayin do not possess the same technological skill as House Eunod, nor the flawless, enduring craftsmanship of House Vhig, but the arcane is most common among them.
Going with a kind of Asian feel to them. Speaking as an East Asian.
As for the shells, here's what I've added:
Physical Description: Alarcrayin resemble large swans of varying color, with two identical, smaller sets of wings above and below the primary set. Children are master flyers from birth, and can eventually forsake the ground entirely.
Alarcrayin also have a hardened golden shell - like a tortoise's - upon their backs. This shell domes over most of their back, but makes significant 'bumpouts' to allow for the many appendages they have. A hatchling Alarcrayin can withdraw its wings into this shell, but by the time the second wingset has begun to form, this is no longer possible.
Alarcrayin decorate their shells as signs of status, using elaborate engravings chiseled by artisans using beak-knives; each engraving indicates an achievement of some kind, often in the realm of psionic advancement. You can tell how old an Alarcrayin is at first glance by the depth and coverage of their shell engravings. Psionically potent members of the race have engravings which glow until they are exhausted of power.
And Vhig Society added:
A hierarchy of leadership is necessary; those Vhig with more mental acuity find themselves adjusted up and down the chain of command early in life, and then remain in a role permanently. This has no social implications; there is simply an understanding that some are more needed for specific roles than others, but that for the society to function, all are necessary. Crime is unheard of among the Vhig, and those who seek to betray their House are rare exceptions; most are the result of magical mental tampering.
I really appreciate these questions, they help me fill out the world. I'd honestly never even thought of doing anything with the shells before, and now there's this really nifty flavor touch there! <3