By eating off stress and pain
Catholicism teaches that Satan and demons are real entities that exist. They are fallen angels. Satan is the leader of the demons. They can possess people. They wish to harm human beings.
Yes
yes
You need to do some research - writers do a lot of that! - and learn all about different types of demons so you can figure out a way to do that on your own. Using someone else's ideas will leave you at risk for getting sued if you sell the story and start making money. HERE is a link to a question about writers and story ideas, too.
The Church teaches that the devil is a real entity. He is a fallen angel. Demons are lesser fallen angels. Demons can possess living persons.
demonologist
Another answer from our community:They pose as people to bring people to Satan(the devil)
im a half demon and i dont but maybe some do it really depends on the demons powers
Yes but be warned demons are unpredictable
You can't possess anybody. That is a lie spread by the Christians and the Jews. Demons don't possess people either. Angels (enemy Nordics) possess Humans sometimes because they are very evil. If you are under the protection of Satan however, you will not have to worry about that. Hopefully you aren't a Satanist because you think it's cool, or think you are "evil" in any way.
it is a way to explain the punishment of evil people.
Roman Catholic AnswerDemons are fallen angels who can possess people, thus devils; so you can assume that is what was possessing Mary Magdalene.