Thusly Reality tends to be the domain of the Shaman, who is able to work magic through rituals. These rituals can be anything from a love spell to communing with the spirits who have taken up domains and residences throughout the city. Most Shamans adhere to one spirit in particular, though they are able to summon any spirit in the city if they know how.
Spirits can grant any number of gifts to their shamans. Smog may make it so toxins cannot hinder his shamans while Hollow may render her shamans invisible so long as they hide within any abandoned or condemend structures. They may also grant temporary boons to a shaman who contacts them, regardless of patronage. These gifts and boons are always conditional, however. A Shaman who breaks the rules of her spirit may quickly find herself without that spirit's patronage anymore, thusly losing any gifts she may have had.
Boons are usually temporary. Something a spirit gives a shaman to keep until they complete a quest or a mission or a job. And the boon always has to do with the job, for a spirit finds it better to help the shaman accomplish their mutual goal. Once the job/quest/mission is complete, the boon is then retracted. This isn't to say a shaman gets nothing out of completing a job for a spirit. If nothing else, gaining the favor of a spirit is in itself a reward. It means less trouble the next time the shaman needs something and must contact that particular spirit.
On the other hand, not completing a quest/job/mission for a spirit means instant revoking of the boon anyway. And, the spirit will not likely make itself available to the shaman if he tried to contact it again, or refuse to help said shaman with whatever he needs.