Very complex subject I thought about writing a grimoire about. This religion has influences from many sources especially Zoroastrianism and Islam. They beliieve God is Melek Taus who is the “peacock angel” that was created by Ahriman or Angra Mainyu according to Zoroastrian lore. This occured when Ahura Mazda challenged Ahriman by stating he was not able to create but only destroy… Ahriman replied by saying essentially “I can create beauty just as you. I just choose not too”.
How this Melek Taus came to be the God of the Yazidi is still unclear to me and I am looking further into it. I do know they are murdered and persecuted till this day by Muslim people as they are considered infidels. Some Yazidi do claim that Melek Taus is the Devil however my intuition tells me this view mainly developed to try and help avoid persecution and/or it is similar to our western gnostic concept of the demiurge dillema.
Regarding magick… it is a religion and so there is not much present. Philosophical ways of thought are strong which can be applied to life to create change as it also has ties to the Sufi tradition. I do know for a fact that very powerful magick can be found through the key of will which seeks to unlock the symbolism within the religion.