Yazidi are a religious group principally composed of Kurds. They are principally located in the middle East. Furthermore their holy site is Mosul, Iraq. They are also present in Eastern Europe, Russia and Germany. Totally they represent 500,000 people. Their origin is not really know. Some say that their religion are a modified version of Islam. Others say that their religion come from Zoroastrians. We don't know neither when their religion born and what was their first leader if they had one. Maybe during the 7th century if it has been influenced by Islam. But several facts contribute to say that their religion are far older and could come from pagan religions. It is even possible as Yazidi say that Zoroaster was a Yazidi. In fact, if we don't really know their religion and myths , it is because of they endured persecutions during all their history. They have been known as satanist because of their god's name "Shaytan" and their philosophy. Because of that they should have hidden themselves and they used cryptic symbol and language to protect their beliefs. It is also a pagan practice.
Their philosophy is really different from any other religion. They are monotheist but their beliefs include seven angels which are considered as lower god. One of them, the most powerful could be compared as Satan in the christian religion. Indeed, from the Yazidi perspective, he didn't follow the order of god to bow Adam because he said that he was more important. Then God makes him the leader of all the other angels and gives him the Earth and he is now the master of the Earth. Yazidi say that this angel, principally known as Malak Ta'us is not evil. He is the angel who represents God on Earth. Evil is only present in the human mind. Human have the choice between good and evil as Malak Tau's had. The new year day for Yazidi is the first apparition of Malak Tau's on Earth the 1st Wednesday of Nisan (March/April). Another particularity of the Yazadi is that they said that they don't come from Adam and Eve but only from Adam. It is why they feel really different from other people. You can only became Yazidi by wedding or by birth.