Satan is a fallen angel whose intent is to supplant God and frustrate his purpose and ultimate end is consignment to eternal punishment (Luke 10:17-18, Revelation 20:10).
Angels
In heaven there is a glorious praise of angels who extol the LORD God Almighty with heavenly praises. It is said that they are gigantic beings with colours that human language cannot describe. John had a vision of the last days, which are recorded in the Book of Revelation; the last book of the Bible. He was taken to heaven and He had an exclusive encounter of the magnificent residence of God and the angels and coming to think of it, he had a pretty hard time describing what he saw. The chance that he did not record most of the occurrences is next to one. He just tries to give us a glimpse of what heaven is like.
He records that there are innumerable angels in heaven by saying that the number was ten thousand times ten thousand. He then adds ‘thousands of thousands’ meaning that they were just too many. You can imagine a choir of this size singing praises to the Almighty. It must be a brilliant voice. This is the sole business that goes on in heaven-worshiping God. If you do not like worship and praise then you are not prepared to go to heaven.
Lucifer
Isaiah 14:12-15 tells us the story of an angel named Lucifer. Lucifer was one of the angels very close to the Most High (God). He led all the angels in praise and worship. However, the element of self got the better of him and he envied God. This consuming element was so strong that he wanted to be God (verse 13-14). He was so determined to be like the Most High; a determination that led him to station a coup in heaven. Since he was just but a servant, he had no power to succeed in his mutiny against his master. Even with a third of the angels (Revelation 12:4) who sided with him, he had no negotiating grounds.
God was of course angered and He had to cast out the obstinate vermin. As merciful as He is, He did not destroy Lucifer then, but eventually, He will pulverize the traitor when the time is come (see verse 15 & Romans 16:20). God sent the angel Michael to exile Lucifer and his followers, an action that caused a war in heaven (Revelation 12:7-9).
Satan’s motives
Lucifer was cast to the world (Revelation 10:9) and the world therefore belonged to him until man was created. Through his treacherous schemes, he gets dominion back after man fell (2 Corinthians 4:4). He is out to deceive the world (see the same verse & 2 Corinthians 11:14) and his main work is to steal, kill and destroy what God had made (John 10:10). For this reason John tells us in 1 John 2:15 to not love the things of this world and if we do then the love of the Father is not in us.
Satan is the author of everything of this world. All the systems including education, government, jobs, technology, entertainment, etc., are all engineered to turn man away from God. It is therefore important for us not to rely on them but to fix our hope on God to avoid the deception. The fate of Satan is already decided and he will be done away with at the end of time (Revelation 20:1-10). He will be thrown into the lake of fire and brimstone and be tormented forever.