Information on the Avis Concelebro race is somewhat scarce. They are said to have a much longer lifespan than normal human beings and all are born with wind Harnesses by default.

The sovereignty of the species are referred to as the Grandaeva. The Grandaeva, consisted of both Alti and non-Alti, is a council of five to seven persons of varying ages (but no younger than 30 years). There is no "head" of the council--instead, members of the Grandaeva have equal power and cannot overrule each other as a result.

All Avis Concelebro are born initially as humans, with the exception of their ability to transform into various bird-like creatures. However, as certain persons age, they begin to take on physical characteristics of birds. Those certain persons are known as the Alti. Notable Alti thus far have been Kee'da Va'Valeo, a deceased, former member of the Grandaeva, and Adizo Desta, a current member of the Grandaeva.