Wyrd and Spirit Traits
Every character has a Wyrd pool; the number of points in this pool represent a character's spiritual heft and destiny - their impact upon the world. A character's Wyrd pool is equal to their average spirit trait, rounded down, and the Wyrd pool refreshes once each IC period. Sometimes, characters may receive an extra point of Wyrd during an IC period because of some great effort, exposure to an alien artifact, or some other reason.
Wyrd can be spent to improve rolls, rescue victory from the jaws of defeat, or rarely to power certain occult rituals. Wyrd spent to improve rolls represents the character's destiny and/or will exerting itself on the world, and a player's choice about when and how to spend Wyrd gives staff a sense about the moments a player thinks are most important to their character's story.
Channeling Spirit Traits
Wyrd spent to improve rolls is 'channeled' through one of a character's four Spirit Traits. By spending a point of Wyrd before a roll, a character can add their spirit trait to the roll, or gain some alternate effect as described below. The alternate effects described at the most common, but others exist at the GM's discretion; a character might be able to spend Wyrd to remain calm and ignore a Mishap, for instance, or Summon Ego to guarantee a 1 VP success on a roll.
A character incites passion when emotions at play or when engaged in some task central to the character's heart, and when inciting passion they are ruled by their heart - driven by love or hate, courage or fear, anger or need.
Characters who Incite Passion spend Wyrd before rolling and add their Passion as a bonus to a single roll. Alternately, if a task is going to require multiple rolls, they can add half their Passion trait (rounded down) as a bonus to a series of linked actions towards one goal.
A character spends Wyrd to remain calm when they need to block out the effects of fear, love, or other emotion to focus with careful deliberation on the task at hand. It is very hard to remain calm when emotion is at stake.
Characters who Remain Calm spend Wyrd before rolling and add their Calm as a bonus to a single roll. Alternately, if they twice as long to perform a task, they can roll twice and pick the best result, adding half their Calm trait as a bonus to each roll.
Call Upon Faith
A character calls upon their faith when they ask the Pancreator or some other higher power to intercede on their behalf. Sometimes, this is not an appeal to some discrete entity; it might be an appeal to a communal spirit, general providence, or fate. The common thread is the character's recognition that they are but a small part in a larger design, and the fervent hope that that larger design will help them.
Characters who Call Upon Faith spend Wyrd before rolling and add their Faith as a bonus to a single roll. Alternately, they can re-roll a roll failed by less than half their Faith trait.
A character summons their ego when they focus on their independence, self-rule, and will, powering through adversity with the confidence that they are the center of their particular drama. Summoning ego is an expression of self-confident grit, an unwillingness to accept the hand that fate has dealt and an overwhelming desire to remake the world as a character wills it.
Characters who Summon Ego spend Wyrd before rolling and add their Ego as a bonus to a single roll. Alternately, they can ignore wound penalties or the effects of mental compulsion for a number of rounds equal to half their Ego trait.
In addition to channeling spirit traits, Wyrd can be spent to snatch victory from the jaws of defeat - but at a price. A character who has failed a roll can spend a point of Wyrd to barely succeed, but their victory will by pyrrhic; in addition to success, they will suffer ill effects similar to a mishap.
This is a sliding scale! A character who spends a point of Wyrd to turn a mishap into a Pyrrhic victory or to defeat an opponent despite an opponent rolling a critical will suffer more substantial ill effects than a character who spends a point of Wyrd to turn a minor failure into a Pyrrhic victory. Similarly, a character who spends Wyrd to gain a Pyrrhic victory in a matter of great importance risks more substantial consequences than a character who spends Wyrd to gain such a victory on an issue that matters little.
Spirit Traits and Rolls
In addition to spending Wyrd to affect rolls through spirit traits, spirit traits say something about the 'balance of humors' in a character and may affect rolls as a consequence. A character with a much higher Passion than Calm, for instance, may take a penalty equal to the difference between the two to a single roll in a very high-stress situation, or may get a bonus equal to the difference when needing to react quickly in a matter of great personal importance. Similarly, a character with a higher Faith than Ego might take a penalty when trying to resist the effects of an alien artifact but a bonus when confronting a demon.
These bonuses and penalties are purely discretionary on the part of the GM, though a player can always take a penalty when they feel it is appropriate. Bonuses and penalties will almost never last for more than a single round and are generally invoked only at dramatically appropriate moments.