The fascinating culture of the Yezidi people was first brought to the attention of the west in the 19th Century by Sir Austen Henry Layard, a British explorer and archaeologist who had encountered them in his quest for the lost city of Nineveh, capital of the ancient Assyrian empire. The people he met were incredibly stalwart in their devotion, but had been forced by well over a millenium of persecution to adopt a significant degree of discretion.
One interesting fact Layard relates in his book, Discovery at Nineveh, is that, although they venerate that entity called "Satan," they never, under any circumstances, actually use that word. Hundreds of years of persecution have made them very cautious, to put it politely. This doesn't just apply to theological contexts, either; it also applies even to those contexts in which even the most fundamentalist Muslim would take no offence. For example, among Muslims, a rambunctious child might be referred to as a little "shaitan," much as in English he would be referred to as a "lil' devil." But when Layard jokingly called a young Yezidi a "shaitan," he alienated the whole tribe of Yezidi with whom he was staying. That is why they refer to "Satan" as "Melek Ta'us," or "Peacock King" — the king of pride, Lucifer, the governor of Earth.
Another important element of their discretion is the transmission of holy texts. Although the Yezidi have a holy book, known simply as the Black Book, it was formerly written in a special alphabet which was reserved specifically for the purpose of making the text impossible for someone to read if they don't know the "code." Furthermore, it is written in the Kurdish tongue, an Indo-European tongue which is mutually unintelligible with both Persian and Arabic (a Semitic tongue). The result is that any non-Yezid would have a very difficult time decoding the text, even if they managed to get their hands on it.
Despite (or perhaps because of) the fact that the Yezidi are Satanists in the most literal sense of the term, they have a very modest lifestyle. Traditionally, they wear simple white or red garments, they don't drink wine or beer, and they obey all laws of kosher, though Yezidi living in Europe are generally more relaxed on these points. Also, a tribe would usually have a copy of the Koran kicking around, so that they can pose as Muslim if they need to.
What circumstances necessitate this humility from a people who worship the angel of pride? Few peoples on Earth are quite as universally reviled as the Yezidi. In the Crusades, it would sometimes happen that Christians and Muslims would actually cease fighting, and team up, just to kill Yezidi. Even other Kurds, who are in general strongly nationalistic, will kill Yezidi for having not converted to Islam. Even today, 30,000 Yezidi live in Diaspora in Germany, because they cannot live in safety in Iraq.
The reason for this persecution, obviously, is Yezidi theology. Although, because of the lack of Yezidi literature, there is no well-worked-out system of theology, the Yezidi religion is clear on certain ideas. God, the Yezidi say, is not personal. "He" is not a "he." It doesn't matter if you "stray" from "his" path; as a matter of fact, God can hardly even be said to have a path, since everyone gets into heaven. This includes Satan.
There is no Hell for the Yezidi. In his 7,000-year exile, Melek Taus's tears extinguished the fires of Hell, which was destroyed when he repented his arrogance. God created the Earth, but gave stewardship of it to the Peacock King and so he is, in a manner of speaking, the god of this world. Those who play by his rules will be rewarded with pleasure, luxury, and achievement; those who turn away from Satan also turn away from the spirit of the world, and will therefore suffer. Now, God does not actually forgive or condemn, and Hell is Earth, and hey, Hell ain't looking so bad. The only real problem with it is the masses upon masses of people who reject Satan, but this rejection is based on a false dichotomy in the eyes of the Yezidi. If there's anything analogous to a personal god in the Yezidi religion, it's Satan. The Yezidi honour Melek Ta'us as the spirit which governs the natural world in all its beauty and bounty.
Today, most Yezidi live in Iraq, Armenia, Georgia, Turkey, and Syria, as well as having a community-in-exile in Germany. In the 21st Century, they have a great deal of freedom that they never enjoyed before, so the Yezidi are starting to practice their religion openly. Although they have no organised church per se, they have a newsletter, Dengê Êzîdiyan ("Voice of the Yezidi"), which serves as an organ of religious tolerance. They have also established a website with a discussion board for those interested in the Yezidi religion.
www.yezidi.org
Noder's Note (September 20, 2001): The following is an exerpt from the Dengê Êzîdiyan international discussion board. It was posted on March 14, 2001 in response to a question regarding the relationship between the Peacock King (Malâk Tâûs) and Satan. Now, I don't speak German (which wasn't this guy's first language anyway), but babelfish.atlavista.com does, so I've translated the gist of the message. Correct me if I'm wrong.
Die Yeziden glauben nicht an der Existenz einer bösen Macht. Im Yezidemtum gibt es nicht die Vorstellung einer anderen Macht, die neben Gott existieren kann. Selbst die Aussprache des Wortes bedeutet die Anerkennung des Bösen und damit die Antastung der Allmächtigkeit Gottes. Deshalb sprechen die Yeziden das Wort nicht aus. Ta´usi-Melek ist also nicht ein Widersacher Gottes. Nach yezidischer Vorstellung ist Ta´usi-Melek der Stellvertreter Gottes. Gott hat Ta´usi-Melek zum Obersten der sieben Engel ernannt, weil er in besonderer Weise Gott geachtet hat. Die Yeziden glauben an einen, guten Gott. Gott kann aber, wenn erforderlich, auch negative Dinge verrichten. Es liegt allein in der Verantwortung der Menschen Gutes und Böses zu tun. Es gibt nicht die Vorstellung von der Hölle. Die Yeziden glauben an die Wiedergeburt.
Denge Ezidiyan
Englische Übersetzung folgt
"The Yezidi do not believe in the existence of an evil power. In Yezidism there is no conception of another power that can exist apart from God. Even the mention of the word ["Satan," which the author diligently refrains from saying] means the acknowledgment of an evil one and thus impinges upon the omnipotence of God. Therefore the Yezidi do not express the word. Tâûsi-Malâk is thus not an adversary of God. In the Yezidi conception, Tâûsi-Malâk is one of the deputies of God. God appointed Tâûsi-Malâk the highest of the seven angels, because he was held in high esteem by God. The Yezidi believe in one, benevolent God. God can, however, if necessary, perform negative acts. It is the responsibility of humans alone to do good or bad. There is no conception of hell. The Yezidi believe in reincarnation.
"Denge Ezidiyan
"English translation follows." (Which, on the message board, it didn't. Go figure.)
This somewhat contradicts some of what I've said before, or may put it into a different perspective. It is, however, straight from the proverbial horse's mouth, and can be considered authoritative.