Firebird Cult
The Firebird Cult is the dominant religion of the Thousand Eyries, and one of the largest religions that fall into the category of Kami worship in Zairis. It reveres Phoenix as the reincarnated form of Ardothun Broken-Wings, the shattered Primordial of the sky, and holds that the Avian Blazes are made in his image and thus destined to rule over both the 'lesser' Avian races as well as the rest of Zairis' civilized peoples.
Spread
The Firebird Cult has the greatest reach within the Thousand Eyries, but is also present in other parts of Zairis. In particular, the Ka'aran desert is a popular pilgrimage site, as it is where the founders of the cult had their vision of Phoenix.
Relations with other religions
The Firebird Cult retains a loose working relationship with the Solar Church, a fellow cult of Phoenix, albeit one with very different beliefs on the nature of Phoenix, which they frequently clash about.
In the Thousand Eyries, they have been at a secret war with the Ten Clouds Cult since roughly 7000 DC, believing that the Ten Clouds Cult is constructing a false idol of corpses, which they see as an affront to Ardothun's reborn form.
Their petition to join the Primordial Faith Authority was rejected.