Ritual Purity Rules

I gotta write this before Arnold does

Based on some recent posts by Arnold K and some older posts on Whose Measure God Could Not Take, as well as the content of Purity and Danger by Mary Douglas.

Ritual Purity is a concept present in most world religions. It is often conflated with, though far less often actually identical to, Morality in the context of world religion. It is, of course, concerned with the distinction between pure and impure, clean and unclean. Generally this is important because being unclean is a dangerous state, or a state unfit to preform necessary or socially acceptable activities. An unclean person is not an evil person or a damned person*. It's the difference between, say, an altar-cloth with a pentagram pattern and a altar-cloth which had someone accidentally bleed on it. One is detestable, the other is simply currently unfit.

Uncleanness is most often spread via physical contact. For instance, in Judaism, it is unclean to touch the dead, or to touch someone who is diseased. Sometimes you become unclean simply from yourself, such as in the case of menstruation or nocturnal emissions. Sometimes you become unclean from necessary activities, such as giving birth or butchering an animal. Sometimes a group of people is naturally unclean, and becomes ostracized.

And of course, there are ways to become clean. Bathing. Sacrifice. Time. Unless, of course, you are inherently unclean.

Ritual Purity almost always has some effect relating to religion, as the name implies. Most often, priests must be clean to go about their duties. Offerings must be clean (or sometimes very unclean), lest you call wrath upon yourself. Magicians, depending on the culture, either had to be very clean or very unclean in order to work their magic. According to Mary Douglas, some amount of purity was always required of the Indian upper caste and those who interacted with them.

Now, some rules.

Purity Scale

[unclean/clean things in square brackets may be substituted in the list on player choice]

• Immaculate: You are almost too pure. The spiritual forces of the world ingratiate themselves to you, and the presence of gods is comfortable to you. Sometimes kings make sacrifices to you. It's really quite inconvenient. Gain 1 [magic], which you can use to cast *any* spell. Alternatively, with a short and well known ritual, you can gain the service of a lesser spirit permanently (this causes you to become unclean). When you become unclean, you take 1d6 damage. If you die before becoming unclean, you trigger a divine cataclysm which consumes the surrounding area (which definitely will kill your allies and level/blight/erase nearby towns). Alternatively, you become an amazing human sacrifice. If anyone can sacrifice you to the gods without causing you to become unclean, they gain two levels and a minor wish (this is vaguely known to everyone who passes a contested wisdom check). Things which are unclean: touching another human, touching dirt, eating, wearing dyed clothes [crying or laughing, walking, having another look on you, talking].
• Pure: You are pure enough to interact safely with divine things. The requisite level of knowledge and wealth needed to maintain this state probably qualifies you to be a priest in a pinch. Sometimes it qualifies you to be the center of a cult. If you can already cast spells, you can cast as though you were one level higher a number of times per day equal to your level, and have +1 on two saves of your choice. Things which are impure to you: Mud, touching Clean people, being wounded, eating meat [speaking above a whisper, speaking less than a shout, wearing mixed fabrics, entering a tomb, drinking alcohol]. Things that make you more pure: blessed springs, miracles, a month of fasting and intense baths, actual fire. 
• Clean: You are pure enough to interact at all with nobility. Most normal people occupy this space, and most of the rest are clean ~30% of the time regardless. No effect. Impure things: Shit, Sex, Blood, Dead Bodies, Being Sick, Eating Impure Things [Stagnant water, having a beard, not having a beard]. Purifying things: a day of heavy washing, confessing sins, being anointed with oil, using a talisman, abstaining from sex and alcohol for a week.
• Unclean: It's mildly rude to talk with clean people. Spells have a X% chance of not working, where X is every hour you have been unclean. Impure things: Necrophilia, touching untouchable people, Coprophagia, demonic food, murder, rape, making unclean sacrifices [tanning animal hides, smithing, vagrancy, leprosy, becoming a scapegoat]
• Untouchable: You are considered disgusting by society, and are heavily discriminated against. You may not be allowed to enter stores or inns, and you certainly can never be seen by a priest. Nothing is more impure than you, and you cannot become clean except by incredible extraneous circumstances. You receive 1 [magic] which may be used to cast impure spells which regenerates at midnight. You can expend this during downtime to make a wealthy-level wage in some impure craft. If you choose to be a member of the untouchable caste at character creation, you get two [magic] instead.