What does the Church teach about Satan and demons?

Satan and demons are real, personal spiritual creatures. God created them good, but they freely and irrevocably rejected Him and now seek to draw human beings away from God.

Who Satan is. Satan is a fallen angel, not a symbol for evil or an equal rival to God. Scripture calls him the devil, the tempter, the father of lies, and the evil one (Mt 4:1-11; Jn 8:44). Other angels followed his rebellion and became demons. The Church teaches that their fall consisted in the free and radical rejection of God and His reign (CCC 391-393). Their choice is irrevocable because of the definitive character of angelic choice, not because God refuses mercy to a repentant creature.

What Satan can and cannot do. The devil tempts, deceives, accuses, and works to separate people from God. He cannot read the human heart as God does, force a person to sin, or overturn divine providence. His power is limited because he remains a creature. Although his activity can cause grave spiritual and even physical harm, God permits it only within His wise providence and can bring good from it (CCC 395). Christ has already conquered Satan through His death and Resurrection (Col 2:15; Heb 2:14).

Temptation and responsibility. Demonic temptation is real, but personal sin still involves human freedom. People should neither blame every sin on a demon nor dismiss spiritual warfare. Christians resist the devil through faith, prayer, the sacraments, obedience to God's commandments, and works of charity. St. James gives a clear pattern: "Submit yourselves to God. Resist the devil, and he will flee from you" (Jas 4:7). Mortal sin should be brought to sacramental confession before receiving Communion (CCC 1457; Canon 916).

Possession and exorcism. Demonic possession is possible but rare. The Church investigates alleged cases carefully and distinguishes possession from physical or psychological illness. A solemn exorcism may be performed only by a priest who has explicit permission from his bishop (CCC 1673). Catholics should avoid occult rituals, mediums, divination, magic, and attempts to communicate with spirits (CCC 2116-2117).

In practice. Keep your attention fixed on Jesus rather than becoming fascinated with demons. Pray the Our Father, receive the sacraments, forgive others, reject occult practices, and seek a priest if you face persistent spiritual distress. Christ is stronger than every power of darkness, and those who remain in Him have firm reason for hope.