Satan has a well structured kingdom, which is working to destroy the lives of human beings. Nothing happens by accident, there are spiritual forces manipulating situations, people and events to work against you. All life is spiritual, what happens in the physical world is an outcome of what has happened in the spiritual world. For you to be successful in spiritual things you cannot ignore this topic, you will need to understand the nature of the adversary, and his modus operandi. Paul wrote, "so that Satan will not outsmart us, for we are familiar with his evil schemes (2Corinthians 2:11)." Ephesian 6:12 For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places.
God has appointed an angel to each and every one of us, whose job is to protect and guide that human being. That Angel’s priority is to ensure that he guides you to a place where you can hear the gospel of Jesus Christ. When you get saved, and receive the Holy Spirit, the Angel starts taking instructions from you because God will be communicating to your spirit directly. When you grow in the things of the spirit, and God increases your authority, he adds more angels, and promote the one who had been with you to be their leader. Likewise Satan also has appointed a demon for each one of us. This demon has been around you ever since you were born, he knows your weaknesses, your past hurts, past failures and mistakes, and can easily whisper such thoughts into your mind. If this demon succeeds in winning you to Satan, he gets promoted, and other demons will be sent to work against you and the one who had been there longer, becomes the chief demon in your life.