Karma for the Gamemaster
Just like the PCs, the Gamemaster (and story) also has a pool of Karma that carries over from encounter to encounter (and from game session to game session).
The GM gains Karma when players spend Karma (including power costs, but not when a player converts a Karma to XP). Anytime that one or more Player Characters spends one or more Karma, the GM adds one Karma to their pool. The GM never gains more than one Karma at a time (unless otherwise specified) and this is the only way that a GM earns Karma.
Whenever the GM earns a Karma, the GM rolls 1d10. If the number rolled is equal or less than the current amount of karma in the pool, the pool is reset to 0, and a Karmic Complication is randomly rolled and added to the story.
The Gamemaster is limited to holding 9 Karma at a time. Any additional Karma earned are discarded (but still trigger a complication check as normal). This ensures that there is always a chance that a Karma spent by PCs won't trigger a complication.