Spirits and Ghosts
General information
The term 'spirit' and the term 'ghost' is often used pretty much interchangably by the general populace. For those people really in the know, the difference between a spirit and a ghost is that a spirit always has some kind of autonomy (ie, spirits as a group do not include repeating phantasms), whereas 'ghost' is a general, catch-all term for anything that's dead and still hanging around in a (largely) non-corporeal form. Looking at it broadly, all spirits are ghosts, but not all ghosts are spirits. And getting right down to it, some spirits can be a little snobbish about terminology and get pissed when people call them ghosts. Others don't really give a damn actually.
Not all people who die become ghosts. The general lore out there is correct - ghosts are often created when someone died with unfinished business of some description. There's a lot of that out there - people who died before their time, or messily. People who didn't want to leave someone else behind. People who were angry at the world. It not always the case that their deaths had to be violent, or traumatic, but something ties them to the mortal realm, even if it's just that they happened to like their life, thank you very much, and were having too good a time to leave yet. Everyone else just merrily goes off to wherever the dead go off to. And no, sorry, spirits don't know where this is any better than the rest of us.
For years, centuries, millenia - forever, in fact, ghosts have only been able to be seen by specific people - mediums, spirit elementals, dreamwalkers etc. For the majority of the populace, ghosts didn't exist. They didn't really see them, hear them, rarely experienced them. Unless a spirit physically manifested in front of them, it was just a trick of the light, or a coincidence that plate fell off the wall at that very moment.
Since Halloween 2007, 'life' for a spirit has changed drastically. The veil between this world and the spirit world got pulled back--and just didn't happen to get dropped back into place. It stayed open. Which means spirits can now be seen by anyone, special abilities to or no. They aren't tricks of the light anymore--they're there.
They can be seen, sure, but still have as much trouble doing anything else as before--however there are places now that they have an easier time with it. Cemeteries, areas close to fae gates or large energy sources - in these types of areas they can communicate with being heard, touch people, interact much more like they were alive again. In other areas, their abilities to do these kind of things is limited and dependent upon what energy is available in an area and in some places, a spirit may, for example, be able to be seen in a ghostly fashion, but may not be able to make themselves heard.
The 'body' of a spirit resides on the spirit plane, but a spirit has a connection to the mortal plane which allows them to 'project' themselves onto the mortal plane to a greater or lesser extent. This is the reason why a spirit will appear 'ghostly' (for want of a better word) - ie, semi-transparent, see-through. It takes energy to achieve anything safe the most basic of projections into the mortal plane. Spirits have an energy charge. They use this to affect the world, to speak across the planes, to be seen or manifest, etc. They can draw this energy from the convergence, or from objects that were important to them in life (you must choose these objects at character creation). Now, this isn't to say that they have a neverending battery supply. Spirits only have so much of a charge they can hold at one time. This partially explains why they can be so erratic. They may run out of energy before they get their message across.
A ghost's appearance is always semi-transparent at best (unless you're a dreamwalker, then you follow the dreamwalker rules for seeing spirits). Unless a spirit is manifested, they do not appear to be solid.
If you walk through a ghost, or a ghost walks through you, or touches you? It's gonna be cold - icy cold. A brush-touch won't hurt, but if, for example, you hold your hand 'in' a ghost for an extended period of time, you run the risk of frostbite. And a ghost walking through you will hurt. They make the immediate area around them cold as well, drawing energy in from heat to be seen. This is not something they can control or turn off.
Where are these spirits? How many of them are there? Well, the ratio between people and spirits is about 15 to 1. Where they are is all over, though there are places that they're more likely to be. There's actually quite a lot of them wandering the lakeshore, walking up and down the beaches or the road that lines the lake. They would be around cemeteries, and the orphanage. They would also be in rather cliche areas as well--crash sites, hotels, theaters, churches, murder sites, funeral homes, hospitals, houses where someone died, where bad things happened, etc--where you'd expect them to be.
Strengths
-Spirits can drain energy out of things around them. This is a new ability (since Halloween 2007), and not all spirits know how to do this, or how to do it effectively, or without harming things. They can most easily steal electricity, draining batteries, power supplies, etc. However the charge they draw in is not equal to what it gives them the ability to do. For instance, if they drain a fresh car battery, that's not going to keep them going like the energizer bunny. They may have time for a short conversation. If they're just draining little things, they can do small things, like expend enough energy to make a knocking sound when someone asks, or to draw attention to themselves.
They can also draw energy from living things--but this is very not good for said living things. Draining a life force from someone or something weakens and brings it closer to death. Plants, for instance, often will die now in the presence of spirits, if they're around too long. They will gain some energy from it, but if it's just say, a small house plant, that isn't going to fuel them very much. If they draw from animals or people, that works much better, but still will not fuel them for long. Also, it will sicken those it takes from. Small amounts of life force drawn will make the subject light headed and woozy or dizzy. Greater amounts will cause longer term illness, and significant amounts can cause terminal illness and eventual death.
In order to draw energy from anything, contact needs to be made with the subject, and any breaking off of that contact stops the transfer entirely and it needs to be re-connected to start up the drain again (note: to draw energy from the earth, the spirit only needs to be standing on it - that is the connection, however they can only draw energy around a radius of 5 ft from themselves at any one time). This could be where legends of spirits stealing children's lives when they sleep comes from, who knows, but where as one time it was an exceedingly rare thing--it's just kicked right back into gear with the veil drawn back.
In theory, spirits can manifest. For most spirits, however, the ability to do this is severely limited. It takes a huge amount of energy to manifest, and therefore is only possible for most spirits in an area such as a graveyard, or around objects which were important to them in life. When spirits manifest they will appear as if they are truly alive – warm and needing to breathe. At the very longest, manifestations will last no longer than a couple of minutes.
Weakness
-Everyone knowing ghosts are around isn't necessarily a great thing for the spirits in question. They've gone from being anonymous to out there, in full view, and it isn't as if they can just choose to disappear again. Many of them bear the injuries of their death, though not all of them do. Their look is very dependent on their own self image, however they feel they should look(though most spirits do not realize this, and therefore never change how they look accordingly. After all, it isn't as if they've seen themselves in mirrors to even know, now is it?) So they frighten people to death a good lot of the time, and while some people wouldn't think so--there is death for the dead. There's exorcism. And no one knows what the hell happens to a spirit when one's eradicated by exorcism, they're just gone.
So, people are afraid of you, you can't hide anymore, suddenly you actually have to deal with people, and oh right--hunters, exorcists, etc. People often times assume a spirit wants to 'move on' but that is not always the case. They're not always some tortured individual who wants nothing more than to tell so-n-so they really loved them all along and just couldn't say it. Sometimes they're just there, hanging out. Sometimes they like their existence. But the world just got one hell of a lot stranger, and they aren't separated out from it properly anymore.
Ghosts 'exist' permanently on the mortal plane - although their physical being remains in the spirit realm at all times other than when they are manifested, they themselves have no knowledge of this. They don't know what's going on in the spirit realm - so no, the ghost you see in the graveyard cannot tell you about what Auntie Joan wanted you to know, or pass you on messages from the other side. Neither do spirits have the ability to travel to any iother plane of existence - they cannot, for example, enter the dreaming, or the inbetween.
Specific types of ghosts
Repeating Phantasms
Repeating phantasms do not have their own will. They do not interact with people, though people may experience the results of their actions. The actions of repeating phantasms vary - some simply stand in one spot, others appear to be stuck in a loop, repeating the same actions over and over and over again.
What repeating phantasms are are spirits with only a small or no energy source to draw on. A spirit needs to draw on energy from the environment around them to be seen, heard etc in this plane, however a spirit without an energy source never disappears completely. The less energy available to a spirit, the less they are 'there'. A spirit with little or no energy available to them will fade and become, well, more ghostly. Eventually they will fade to such an extent that they can be overlooked by people, and even may start to flicker in and out of existence. A spirit at this level also loses their ability to think and reason - hence why they often simply stop, or get stuck in a repeating pattern.
Any repeating phantasm which is successfully interrupted from their actions and introduced to an energy source again can regain previous functionality.
Bound Spirits
If repeating phantasms are the weakest type of ghosts, then bound spirits would be considered the strongest. They have the firmest connection to the mortal plane, as their connection to the mortal plane comes from something other than themselves. Bound spirits can never become repeating phantasms, and have greater control over their energy usage.
Strengths
-They have one special ability (to be chosen upon character creation) which is generally elemental or forces based, for example the ability to call down lightening, or affect fire etc.
-Bound spirits have an easier time of existence than other types of spirits, because they are much better at channelling their energy. They will never become repeating phantasms due to lack of energy and they don't have to draw from living things so much to be able to communicate. Once upon a time, they could even manifest at will, for up to five minutes a day. That's changed now though - the lifting of the veil on halloween 2007 might have been a bonus for a lot of spirits, but bound spirits got the raw end of the deal. They can now only manifest in areas of high energy, but they can manifest for longer than normal spirits. The length of time depends on the amount of energy in an area.
Weakness
-They only have a set amount of energy available for manifestation every day and it is only available for that day. So they may be able to burn a building to the ground, but if that uses up their energy for the day, there's no manifesting that day. And if they don't use their energy for one day? It doesn't tick over to the next. Think of it like a battery - a 9volt battery doesn't hold a 12 volt charge. They have a limit to how much energy they can carry.
-They are stuck to a geographical area. There is no moving on, there is no getting away. If they do find someone who can see and talk to them? They get to watch that person grow old and die. Or move away from the area. This? Is all there is and all there will ever be. And they can never get away from it.