Death opens the door to things unknowable by the living. A wraith is Fettered and limited, but also holds great potential to change herself or her surroundings. Those who know, who can unravel the secrets of death, find themselves capable of strange powers called Arcanoi. Arcanoi are secrets that can be either learned at the foot of another or acquired through experience. They are ways of using a wraith's spiritual being to alter other aspects of the Underworld, or in some cases the Skinlands. In many ways, an Arcanos is as much a philosophy as a craft, made of equal parts viewpoint and skill. Most wraiths demonstrate aptitude for one or two Arcanoi immediately upon their rebirth, and quickly learn the first few powers, or arts, of those Arcanoi. In game terms, the higher the art level (represented by the number of dots characters before its listing), the higher its cost is likely to be, the more difficult it is to learn, and more powerful it is. Submerging oneself in the practice of an Arcanos can mark a wraith with a trace of that power. These marks make her recognizable as one who is well-versed in a specific arcane skill, and cannot be removed by cosmetic alteration. The deatils vary from Arcanos to Arcanos.
Arcanos Markings Excessive use of an Arcanos will mark a wraith permanently, whether or not she is a member of the Guild associated with that particular Arcanos. A wraith diving into the Tempest with Argos on a regular basis will acquire jet-black eyes, even if she has never met an "offical" Harbinger. It is the Arcanos itself (or the environment associated with its use) that creates the markings, not any sort of Guild affiliation. However, there are many wraiths who have learned more than one Arcanos to such an extent that they start developing more that one set of distinctive marks. This is no longer uncommon in Stygie where average citizens are encouraged to learn multiple Arcanoi. Usually, the multitalented wraith will manifest the distinctive patterns of all Arcanoi she uses, unless there is some conflict between the developing marks (i.e., Argos and Intimation modify the appearance of the user's eyes in mutually excessive ways). In this case, the markings of the Arcanos that is used more frequently will predominate, though some evidence of less commonly used arts will manifest as well. For example, a Harbinger with some knowledge of Intimation (which stains its user's left eye bright green) will have the traditional set of jet-black eyes, but with a distinctively green sheen to his left one.
Wherefores
Environment affects an Arcanos' use, The living can deny death's power, making Arcanoi more difficult to activate. This barrier is the Shroud, the wall between the lands of the living and the dead. The Shroud is usually rated at 9, but weakens in some places or at some times. For example, the Shroud lessens in cemeteries, on Halloween or on other occasions popularly linked with the dead. The Shroud is also less powerful in a wraith's Haunt. Whatever the circumstance, though, the Shroud rating never falls below 4.
Attunement
Attunement is a process of gradually practicing an Arcanos on a certain subject, investing Willpower so that the Arcanos becomes easier when dealing with that person or object. This process is mainly used with Embody, Puppetry and Inhabit, although the Storyteller is free to allow her players to attune other Arcanoi (such as Usury or Pandemonium). People that a wraith has attuned to are usually called Consorts. Each time the wraith successfully manifests to, Skinrides or hides in the object, she may spend one Willpower point, carefully identifying with it. The closer the wraith was in life to the object, the easier attunement is. Attuning to a stranger costs five Willpower; attuning to a close friend or lover may require only two or three. The results vary by Arcanos; for instance, certain Puppetry arts can only be used on Consorts. If no attunement results are given under the Arcanos, the Storyteller should pick whatever effect seems most reasonable -- if she decides to allow it to be attuned at all.
Wraith Characteristics
Being a wraith does come with certain innate advantages. All wraiths, by virtue of their ghostly nature, possess the following abilities: Deathsight -- Existing on the far side of the grave, wraiths see the world through coffin-colored glasses. Buildings appear to be tumbling down, plants are withered and sere, cars look to be dented wrecks years before their time and people close to death bear a corpse's pallor. Wraiths can see how deeply things -- and people -- have been tainted with the touch of Oblivion. While this may seem to be a drawback, it does allow wraiths to assess an object's weaknesses or the general health of a living being. Lifesight -- Just as they can see the death in beings, wraiths can also see the life in them as well. This ability takes the form of being able to read the auras of living (or at least animate) beings, the swirling veils of color that surround all things. As auras change color from moment to moment according to the mood and health of the beings generating them, wraiths can often determine the current mood, health and state of mind of someone just by looking at her. Sharpened Senses -- All wraiths have an extraordinary sensitivity to sensory input. Hearing whispers and reading the fine print present no problems to any wraith. Among other uses, this can be handy for reading license plate numbers, eavesdropping on secretive conversations and detecting the first whiff of gasoline as an arsonist starts to employ his tools on a Haunt. On the other hand, bright lights, loud noises and other excessive stimuli can be extraordinarily uncomfortable for the Restless, dazzling, stunning or even hurting them. Insubstantiality -- At once, the great blessing and the great curse of wraithly existence, insubstantiality is what allows wraiths to pass through solid objects with a minimum of difficulty. By expending a small amount of Corpus, wraiths can walk through walls, people or bullets with ease.
Below are links to the Arcanoi. The last three: Flux, Intimation and Mnemosynis are harder to get a hold of because the Guilds that founded them, have been banished from Stygia.