What does the Bible say about demons?

Demons, according to the Bible, are fallen angels who once served God but chose rebellion against Him. They are often portrayed as evil and unclean spirits that continue to propagate sin and chaos in the world. Scripture mentions that demons are under the authority of Satan, who leads them in their opposition to God and His creation. Notably, the New Testament emphasizes that demons recognize Jesus as the Holy One of God and tremble in fear of His authority, which demonstrates their limited power in comparison to God's authority. They actively seek to lead believers astray and afflict humans with physical and spiritual disorders.