Unlike players, the GM only gets one “colour” of dice – the colour of stress. The GM’s dice represent the level of difficulty that her side of the conflict represents.
For the most part, wizards are powerful enough that conflict with individual mundanes is trivial and not worth rolling for. The Gift, combined with the training received from The Order, makes wizards both physically and mentally far tougher than any normal person. If a wizard wants a peasant to become a newt, that peasant is now a newt (or dead, or convinced to do something, or whatever the wizard decides).
Overcoming a small group of trained soldiers (or equivalent specialists in non-combat situations) is about the starting place for difficulty (1). Defeating an army of several hundred soldiers (assuming they have no wizard of their own) would be fairly difficult (5 or 6). Non-wizard opponents with the Gift have a stress level of 1 or 2. Enemy wizards range in power from neophytes (3) to archmages (10). Powerful demons, dragons, and other extraplanar creatures have stress levels similar to wizards.
Obstacles and opponents are given a particular stress rating indicating how challenging it is to get into a conflict with them. If a protagonist is facing several opponents at once, take the stress rating of the highest one, and add another die of stress for each additional opponent – add two if they share the same stress rating as the “leader”.
When determining the level of stress, keep in mind that the best a protagonist can do safely (i.e., just using gift) is get three successes, so any stress rating above three is reasonably significant – and any rating above six demands, due to the average number of successes (more than three), that the protagonist move into risky territory.
When the GM rolls stress dice in a conflict, she is bringing potential consequences to bear on the protagonist. At their simplest, stress dice may just provide a number of successes indicating that the opposition, not the protagonist, has won the conflict.
But when stress dominates, regardless of the outcome, the situation exacts a price on the protagonist – in the case of a loss the loss may well be price enough (depending on how bad the defeat is), but in the case of a victory, the victory must take something out of the victor. To put it simply, when stress dominates… stress dominates.
This has a game effect of requiring the player to place a token of fear into the GM’s fear coffer (see Tokens for more info).