Satan
According to Christianity, Satan tried to become God himself, and was banished from heaven for his attempt. This derives from parts of the Bible, in which a star is said to try to make himself equal to God. This star is called Lucifer and interpreted as Satan. Some Christians make a distinction between Satan and Lucifer. In this case, Satan is Lucifers' general. Satan would serve Lucifer on earth, because Lucifer is chained in the underworld.