In Milton's Paradise Lost, Azazil is the standard-bearer of the infernal host. According to the Koran, when God commanded the angels to worship Adam, Azazil replied, “Why should the son of fire fall down before a son of clay?” and God cast him out of heaven. His name was then changed to Eblis , which means “despair.”
Then straight commands that at the warlike sound Of trumpets loud, and clarions, be upreared His mighty standard; that proud honour claimed Azazil, as his right, a cherub tall.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894