When we think of demons, we think of an evil, nasty, spirit. The term demon did not always mean that, in its greek origin δαίμων (daimōn) the term was used to refer to any divine entity. It was when christians and the christian faith seem to take over in Rome which already had adapted the greek use of the term, and spread through out the world that the term demon came to be of meaning of an evil spirit. Actually, I believe that a demon is an entity. The word entity can mean several things. For use in my paranormal field of research and, this entry of the Paranormal Corner, we will refer to the term demon as an evil nasty dangerous entity. A demon was never of this earth and in christian beliefs, demons are the angels that were cast into hell from heaven along with Satan, making the term demons and devils equivalents.
The real problem with a demon is that you could have one in your home and not really know it. As described in Miracles - Gift of Tongue Xenoglossy, a demonic entity tricked someone thinking it was performing miracles and was a good entity. In another account The Possessed Role Play Game book a demonic entity entered a friend of mine through a book describing demonic channeling and conjurations for a game. Another example that show some typical signs of the demonic is in Three Scratches. Demons are also considered by some to be of a different dimension, making them ultra-terrestrial beings. Oppressions and Possessions are some also some of the other tail signs of a Demonic entity at play. Sometimes one get opened up for demonic possessions through practice of black magic or use of Ouija boards, Like described in the entry My first exorcism by Rev. Alaina Damewood. And the entries Possessions and Mary and the Quija Board by Jose Prado. Some members of the demonic are half-breeds like the Hags (Demon witches). Demons are universally affected by Salt, which is used in both protection against and in part for exorcisms.
I am sure that you would know that something was going on and, you may even that there we some kind of paranormal activity happening but, would you be able to tell it was demonic activity? A demon can fool you and make you think it is a nice spirit or a spirit of a loved one that has passed on. After it gains your trust a demon will start it's attacks on you, they are very patient and sometimes wait years slowly breaking you down and then one day moving in for the final blow. Demons can indeed cause you harm and have been known to even make people kill themselves. A demon will have no problem with taking over your body when it has got a foothold by having you accepting it and welcome it into yourself and thus using yourself to make you do its will.
Two of the fastest ways that I know of to cause a demon yo attack you and ruin every thing you have including your relationships, home, job,and even your life, is to use an ouija board and, or attempt a seances. An ouija board should never be used for any reason and a seances should only be attempted with a qualified medium! Even then, there is a chance that an inhuman manifestation could come into your life because you have just opened the door for it by having a seances. You have then in fact, invited it in, an good example how wrong things could go is in the can be read in the entry Mary and the Quija Board.
Some people say you can tell if a spirit is demonic or not by the odor it may cause. An odor of burning, rotten flesh is at times associated with a demonic haunting. A demonic haunting is an intelligent haunting because it can scheme and it is destructive of the person or persons that it is attacking, other phenomena known to be associated with demonic possessions is xenoglossy and phantomania, though phantomania could be present in non demonic experiences too.
There are some people that do not believe in demons as evil inhuman manifestations from Hell. These people tend to believe that some people are the demons and that they are indeed evil people. Everyone is free to believe what ever they choose to believe. For myself, I believe that demons from Hell and other places do indeed exist.
I would advise anyone who has reason to believe that they or a loved one or friend is being possessed by a demon or has a demonic haunting in the home or even on their land to contact a local paranormal investigation team for help and for the most part, paranormal teams do NOT charge for their services. Usually, once a person is possessed by a demon, a blessing needs to be done along with a house blessing and, cleansing along with a religious ceremony and, sometimes a deliverance or if accepted by the Catholic Church as a demonic haunting one could get someone from the Catholic Church to perform the approved exorcism, this is not the only way to do an exorcism, other religions than the christian church can also do this, as described in the entry Remote Exorcism.
Evil entities are mentioned in all religion even though the name for them differ the description of them are eerily similar pointing to the fact that this type of evil demonic haunting is universal and in opposition to all benevolent entities or angelic entities if you like.