I didn't post it because it was a lot of information, but I'll post it here and answer any questions you have.
Also, this might be going into Casual RPing, but it depends on who all is comfortable with what level.

Priests: These guys can be of any religion, race, gender, or soul type. What matters is that they can enter the bubbles between dimensions and destroy the monsters within them. They usually have a soul bound weapon that they can use to vanquish these monsters as well as abilities that only they can use. Priests are what you'll be playing as.

Soul Weapons: Forged out of the soul energy of a Priest, they can take literally any shape as long as the Priest can use it. These are more powerful against Blisters and Demons, and doesn't affect humans or ghosts at all. At most they tickle mortals.

Blisters: Not to be confused with the kind that appear on your skin, these are commonly people who have died a violent death and and are sort of 'stuck' between worlds. They retain the shape they were in when they died, i.e., they have stab wounds, contorted limbs, all sorts of fun stuff. If left alone over a long time, they manifest in this dimension as a sort of 'ghost imprint'. If left alone even longer, they manifest as a monster in the real world, keeping the form they died in and basically eating the living out of jealousy.

Ghosts: Someone who has more business to do, but died a relatively peaceful death. They can only be seen by people who can mediate. These ghosts can enter Blister Areas, but they are only as useful as they were when they were alive. In other words, not very useful.

Blister Areas: When a Blister is formed, they create an area similar to where they died. The longer a Blister has existed, the larger and more twisted the Blister Area appears.

Angelists: Crazy lunatics that think they can convince Priests and the Angel/Horseman of Death to turn back the flow of Death. They'll go to any length to attain their goals. They can summon Blisters at will and use their soul energy to have the Blister to be able manifest.

The Four Horsemen: Beings that are banded together by the Angel of Death, but other than that they couldn't be more different. They keep balance and order, but prefer to keep to themselves.

Bi-Dimensional: Okay, so we live in one universe and the dead cross to the other. Sometimes more violent souls get stuck between them and bleed back through into our dimension. As you can guess, this is very, very bad. Priests can travel into the spaces between dimensions, but anyone who has attempted to cross over completely has never come back.

Soul Types:
Black: Pure black souls don't exist in humans outside of a few exceptions. These typically belong to people who were murderers and died a violent death. They become demons, which after a short amount of time in a Blister Area, manifest in the real world and possess people. They tend to be silver tongued and violently resistant to crossing over.
Grey: Average soul. Neither good nor bad. All humans have a range of grey souls.
White Souls: Typically belonging to Angels, or people who have died that have kind souls. Mother Theresa would be an Angel, for example. There aren't many of these.
Hollow Souls: These souls are empty until acted upon by a White or Black soul. This usually means touching one or being near one depending on the strength of the soul. They are compelled to do whatever the soul they have tells them to do until they absorb it completely. Then they continue to be influenced by that soul alignment, often time presenting traits from that soul. Until they have a black or white soul, this presents as depression, or an absence of feelings, empathy, or just emptiness in general. These souls are rare, formed by typically a lonely childhood or a 'birth defect' that leaves the child listless and in a vegetable state until their soul is filled. Typically it is the former.