The only fallen angel the Bible explicitly names is Lucifer. He is a fallen angel that was once the choirmaster of music in heaven and was the most beautiful of all angels. Lucifer was banished from heaven because he tried to he take God's supreme place in heaven. In the Christian tradition, Lucifer is basically Satan or the devil. Lucifer is the archenemy of God and looks to destroy humankind and bring people to dwell with him in hell.
The name Lucifer means morning star. The Old Testament book, Isaiah 14 discusses in detail about the reasons that Lucifer was cast down from heaven. God relegated Lucifer to dwell in the deep pits of the earth, better known as hell. With Lucifer, God also sent the unnamed angels that supported him to dwell in hell.
Lucifer fights God to possess the souls of humankind by tempting them to sin and turn away from God. Lucifer's minions are called demons, who are evil spirits that can posses the souls of human beings and spur them to commit sinful acts. Lucifer ultimately represents anything that is evil and the antithesis of God's commands. In the Bible, Lucifer succeeded in causing the first man and woman to fall from the Garden of Eden by convincing them to sin against God.