‘I am not out of breath,’ I said between gasps. ‘I appear to be out of breath because you assume that I should be but in fact I have no breath to be out of. You see, although you imagine my form, I exist independently from it. Although I appear to be a postman, I am not a postman. I have taken a form that is appropriate for this meeting but I can take any form. My form is meaningful; it is symbolic of my nature. Like a postman, I am a messenger.
You may be interested in “The Slayer of Souls” by Robert Chambers, an occult romance which includes, among other things, a fictional reference to the “Yezidee” or Yezidi.
The Yezidi are mentioned in various sources, not the least of which are in the works and life of Sir Richard Francis Burton, including The Kasîdah of Hâjî Abdû El-Yezdî [PDF], and in an unpublished section of Aleister Crowley’s introduction to the New Commentary to Liber Legis:
“Aiwaz is not (as I had supposed) a mere formula, like many angelic names, but is the true most ancient name of the God of the Yezidis, and thus returns to the highest Antiquity. Our work is therefore historically authentic, the rediscovery of the Sumerian Tradition.” [via]
Although it’s not a direct reference, to that passage by Crowley, Hymeneaus Beta notes in the Editor’s Introduction of Magick: Book 4, Liber ABA the connection between this “God of the Yezidis”, as that likely was used to mean at that time, and Melek Ta’us, the peacock angel of the Yezidi. The connection is more certainly what Crowley meant because further on in that unpublished introduction to Liber Legis there is mention of “Aiwaz” meaning “Messenger”, which is one of the characteristics of Melek Ta’us.
One of the places that I’ve encountered the deity Melek Ta’us is as he appears within the Feri Tradition, and discussion can be found about that online of which one example is at Feri Tradition: FAQ. There’s a lot more about the Yezidi and Melek Ta’us (also transliterated variously as Tawûsê Melek, Malak Tawus, or Malik Taws, Melek Taus …) online.
But, after that digression, back the the work of Chambers:
There’s an interesting review The Repairer of Reputations: The Slayer of Souls by Robert Chambers from pornokitch where they’ve been reading through Chambers’ works, trying to decide whether history has been just or unjust to Robert Chambers.