"The hero of yesterday becomes the tyrant of tomorrow, unless he crucifies himself today."
An arche was your character's previous orientation on the Moral compass. To understand who your character was before your psyche replaced them, discover your arche and keep it in mind. "Goodness" is subjective and means different things to different people, and how your character defined this defined their lives. What you do and who you will be now is up to you, but altering the course of a character's life in media res may prove harder than you realize or come with unforeseen consequences.
An arche is discovered at the intersection point of two spectra: how a character psychologically viewed the Social Contract (dictated by upbringing, life experiences, and psychological traumas), and how physically capable they were of perceiving and correctly interpreting human emotion (dictated by their birth, genetics, and physical traumas). Where these lines meet creates the perspective from which your character created their morality and how that morality impacted their own behavior or ad hoc helped them to rationalize it.
Even numina have arches; however, it is at the numen level and beyond that creatures begin to either transcend morality, fall in superposition on the compass (occupy several moral perspectives at once), or by their nature confound categorization.
A psyche is your nervous system and its combined perceptions and self-perceptions. Some psyches allow other arches to define their arches, sleepwalking as abstract concepts not their own. Mostly, these arches do not match their psyches, and some are in direct opposition. This at best becomes a struggle to overcome what feels like fate, and at worst, horrible disorders of the psyche attempting to force the immutable (itself) to match an incorrect abstraction. In truth, it is impossible for an arche to "possess" the wrong psyche--only for a psyche to incorrectly abstract itself, causing cognitive dissonance. If one self-defines, that is matches the abstraction to its appropriate psyche rather than trying to alter the psyche to match a desired or incorrectly applied abstraction, many psychological stresses lessen and lucidity is gained.
Other issues arrive from the divorcing of the bodily experience from the psyche (such as in the common misapprehensions of the "soul"), leaving the very base abstraction of our existence indefinite and vague. "You", i.e. your psyche, i.e. the collected perceptions and self-perceptions of a nervous system, is synonymous with the body (sensory organs) and nervous system that do the perceiving. Psyches attempting to separate the two become tangled in an endless and futile attempt to match two false abstractions, of a body in isolation and of an ethereal soul. This leads to the same dissonance as not self-defining. One should always choose an abstraction based on the actual psyche, not attempt to change the psyche to match a desired abstraction.
In times of high psychological stress, if Lucidity is drained, the arche can gain control over the body, reducing sentient beings to an abstract state void of personal will. In extreme cases, this can lead to permanent personality disruption. Depending on the arche's position on the Moral compass, this can range from chaos-inspiring to absolute devastation.
Controlled, light physical stress can restore mind-body cohesion and restore the psyche. Similarly, mental stress can restore the arche if one has been reduced to an animal state.
Because an arche is a neurological and sociological intersection, discovery of a character's arche is two rolls on a D4. The first roll dictates the character's cardinal (nature), the second, their ordinal (nurture) orientation. Phantasms are inflexible, and only change upon Legendary status in Awe. In Tabula Rasa and Method play modes, the Director rolls this stat and you have to deduce who your character was by paying attention to the context provided by NPCs, both their behavior and anecdotes about your character.
1. The Cooperator
Cooperators equated Goodness with Peace, and followed and enforced the rules or laws of the societies and groups to which they belonged in order to enforce order.
- Empathic Cooperator: The Servant
- Psychopathic Cooperator: The Politician
- Relativistic or Pure Cooperator: The Soldier
- Sociopathic Cooperator: The Assassin
2. The Contrarian
Contrarians equated Goodness with Justice, and broke laws and pushed back against authority and power structures to bring about equality.
- Empathic Contrarian: The Punk
- Psychopathic Contrarian: The Revolutionary
- Relativistic or Pure Contrarian: The Journalist
- Sociopathic Contrarian: The Saboteur
3. The Observer
Observers equated Goodness with Truth, and maintained emotional or psychological distance to prevent fallacies and see objectively.
- Empathic Observer: The Poet
- Psychopathic Observer: The Survivor
- Relativistic or Pure Observer: The Scientist
- Sociopathic Observer: The Theorist
4. The Hermit
Hermits equated Goodness with Freedom, and maintained physical distance from other people or society to remain free and so as to not inhibit others.
- Empathic Hermit: The Recluse
- Psychopathic Hermit: The Narcissist
- Relativistic or Pure Hermit: The Libertarian
- Sociopathic Hermit: The Transient
- Joseph Campbell, The Hero with a Thousand Faces, Part 2, Chapter III