As an adult, Jesus encountered wicked spirit creatures. They recognized Jesus and addressed him as the “Son of God.” Jesus likewise knew who they were. They were not spirits of dead humans. Rather, Jesus identified them as “demons,” or unclean spirits.—Matthew 8:29-31; 10:8; Mark 5:8.
The Bible speaks of spirits loyal to God and of those who have rebelled against him. The book of Genesis says that when Jehovah drove disobedient Adam and Eve out of the garden of Eden, he posted cherubs, or angels, to the east of the garden to prevent anyone from entering it. (Genesis 3:24) This was apparently the first time that spirits became visible to humans.
Some time later, a number of angels came to earth and took on human form. Jehovah had not commissioned them to carry out any assignment on earth. Instead, they “forsook their own proper dwelling place” in the spirit realm. (Jude 6) Their motives were selfish. They took wives, who gave birth to hybrid offspring called Nephilim. The Nephilim and their rebellious fathers filled the earth with violence and other great badness. (Genesis 6:1-5) Jehovah dealt with the situation by bringing the global Deluge of Noah’s day. Floodwaters destroyed wicked men and women as well as the hybrids. What happened to the angels?
The Flood forced them back into the spirit realm. Jehovah, however, prevented them from resuming “their original position.” (Jude 6) The Bible states: “God did not hold back from punishing the angels that sinned, but, by throwing them into Tartarus, delivered them to pits of dense darkness to be reserved for judgment.”—2 Peter 2:4.
Tartarus is not a particular location; it is a prisonlike, abased condition that limits the activity of these outcasts. The demons can no longer materialize, but they still have great power and influence over minds and lives. They can possess humans and animals. (Matthew 12:43-45; Luke 8:27-33)
They also deceive humans by posing as the spirits of the dead. Why? To keep people from worshipping Jehovah in a way that pleases him and to confuse them regarding the real condition of the dead.