im grouping these two together for the post even though a ghost or spirit is not automatically hostile, because there is one large fact to get to right away.
a spirit is capable of lying about its identity, and ones with hostile intentions may not answer when questioned, or get offended at being asked.
ghosts are just the spirits of dead humans
the Christians like to use this fact as proof all of them are the devil, but really its more like some of them are okay, and others arnt. some of them lie, others are truthful. some are helpful, others are hurtful. many others are just plain neutral. you have to verify things to avoid meeting something hostile, and this is why occult defense is a studied topic. many of these entities may be randomly roaming around and/or attracted to sources of occult power. much of your motivation to keep them out of places they shouldn't go, are the same reasons you don't let raccoons eat your garbage, or let homeless people squat in your house. that's not being mean toward them, its just a bit of common sense.
when trying to contact the dead, you might find either a ghost or a spirit. if its a spirit coming to the site far afterwards, they might lie and pretend to be that ghost. as a general rule, a death that happened recently is more likely to draw out the real ghost, rather then a death that happened years ago where the original ghost might not be present anymore
-spirits of dead humans still on this earth for various reasons
-verify identity, the sooner to the death it is, the more likely it is to be them
-very expressive, very human
-moody sometimes in that unresolved deaths or terrible deaths leave them with no resolution sometimes, thus trapping them
-regular contact and offering to known and identified ghosts calm haunting and general spooky activity, also caring for the dead is a good public service
-putting them to rest may require specific tasks or actions, i cannot give advice on any specific situation.
-MANY types, from MANY pantheons, and MANY that might not be on anyone's belief system but still get along fine anyways. these are best treated as a broad type of non-corporeal entity who can interact with the world and humanity
-logical theory would suggest that a defense mechanism works if it is believed to work, regardless of whose defense mechanism it is. by all occult logic, a prayer to the christian god and a norse ward rune would presumably both block out hostile spirits. if it is believed to protect you spiritually, it presumably will. an observation i make, is that the most basic type of ritual any belief system has, is hallowing an area of hostile spirits at a bare minimum. if you cant clean out your work area, then there's little else you can accomplish, right?
-often wandering, found in the wild, or drifting in from the wild
-can sometimes lie about who they are. see the previous information
-not all evil. not all good. not all neutral. trust your gut judgement
-the occult equivalent of deer that come into your yard to eat plants and grass, or sometimes raccoons that rifle through your garbage. SOME OF THESE, OBVIOUSLY, MIGHT BE OF A MORE DANGEROUS VARIETY.
-specific types may be attracted by either thinking, reading ,or obsessing about them. invocation calls the named entity to where you are