Yezidi

The Yezidi were an ethnic group from Kurdistan. They venerated the Peacock Angel.

According to The Cult of the Peacock Angel: A Short Account of the Yezidi Tribes of Kurdistan by R. W. H. Empson and Richard Carnac Temple, the Yezidi's Peacock Angel was Satan, and an evil sect of Yezidi worshipped an evil, leprous version of the deity called the White Peacock. (PROSE: The Book of the War)

Behind the scenes
While the Yezidi, or Yazidi do worship a divinity in the form of a peacock, it's not the case that this is identifiable with Abrahamic notions of Satan - such as the idea of a war leader rebelling. The general association of the two comes from an Islamic parable about Iblis refusing to kneel to Adam, which is seen as an act of hubris and defiance. The Yazidi religion similarly shows their peacock divinity refusing to bow to the first man, but it does so after previously being instructed to bow to nobody but God, so it's seen as an act of piety and passing a test. The similarity of these two stories has led to the Yazidi being persecuted by Muslims who have interpreted them as worshipping Satan.