The existence of demons is de fide, defined dogma. The Fourth Lateran Council declared that “Satan and the other devils are 1) by nature spirits…2) created by God, 3) and originally good 4) but fell into sin 5) of their own free will and that they are eternally damned. The new Cathechism repeats this (391-95).
2. How did angels fall and become demons?*
Angels were created with free will and rested in heaven, as we were on earth. In the Garden of Eden
God revealed to the angels his plan to not only to create man but to incarnate himself in man, in Jesus. Some chose to love and serve God. Others chose to rebel. Satan and the other angels refused to accept this plan and bow to a God of flesh and blood. The first sin is pride, “Non serviam”, “I will not serve.”
“Scripture speaks of a sin of these angels. This “fall” consists in the free choice of these created spirits, who radically and irrevocably rejected God and his reign. We find reflection of that rebellion in the tempter’s words to our first parents: “You will be like God.” The devil “has sinned from the beginning,” he is “a liar and the father of lies.”
It is the irrevocable character of their choice, and not a defect in the infinite divine mercy that makes the angels’ sin inforgivable. There is no repentance for the angels after their fall, just as there is no repentance in men after their death.”
The “war in heaven” that erupted when Lucifer (light-bearer) became Satan (the Accuser) is described in the Bible passages:
“Now war arose in heaven “Michael (whose name means “Who is like God?” and thus shows the lie of Satan’s pride) and his angels fighting against the dragon (Satan); and the dragon and his angels fought, but they were defeated and there was no longer any place for them in heaven. And the great dragon was thrown down, that ancient serpent, who is called the Devil and Satan, the deceiver of the whole world—he was thrown down to the earth, and his angels were thrown down with him.”
3. Is possession contagious?
No. You cannot be possessed by being in the same room as a possessed or oppressed person. Nor can you get possessed by being in a room where pray-overs were done.
4. What physical troubles can the Devil cause?**
Various types, ranging from bodily possession, to torments, illnesses, and possession of your home. Demon-possessed people, that is, those whose body has physically been invaded by satanic spirits, are very rare. But there are many people who are disturbed or oppressed by Satan.
5. Who can catch Satan’s eye?**
Anyone. I have had cases involving people from all walks of life: simple people, housewives but also professors, doctors and politicians, lay people as well as priests and nuns. It is important to specify that demonic possession and obsession involves the body. Satan can affect someone’s body but never their soul. He can only become the master of someone’s soul if the person hands it over to him by his/her own free will. Thus anyone can end up Satan’s grip. There have even been saints who have been seriously disturbed by Satan’s force.
6. Are there other creatures on the earth aside from man and the angels?
Examples of these are fairies, elves, dwarves, mermaids gnomes. In the Philippines they are known as diwata, higante, tikbalang, dwende, nuno sa punso, siokoy, sirena, tiyanak etc.
It is wrong to accept the prevalent opinion that there are spiritual beings that are not mentioned in the Bible. These are the invention of spiritists, of followers of the occult, of those who espouse reincarnation, or of those who believe in ”wandering souls”. There are no good spirits other than angels and no evil spirits other than demons.***
* Angels (and Demons) Peter Kreeft
***Fr. Gabrielle Amorthe