Oaths
fairy gifts: you mean no harm to me and mine, you will swear it 89
The Ancient Bargain & Lies
Mercy Thompson Series #3: Iron Kissed
 most fae cannot tell a lie
 
 they are very, very good at making you think they are saying one thing, when they mean another, but they cannot lie
 
 they can do the damnedest thing with the truth, but they cannot lie
 
 a conversation with someone who can't lie is the questions they don't answer
 
Mercy Thompson Series #11: Storm Cursed
 goblins are a part of that ancient bargain18
 
 if the powers that be hear us lie, a terrible and mortal fate comes to us, as to all fae18
 
 those greater in power may fight off their fate for a time, but for the lesser fae, like goblins, we die the moment a lie, knowingly spoken, leaves our lips18
 
Mercy Thompson Series #12: Smoke Bitten
 fae are creatures whose lives are bound by rules282
 
 that they cannot lie being the core rule all of them must follow282
 
 important thing to remember about the rules is that they constrain all of the fae; but only the fae282
 
 the fae can lie—they just suffer a horrible fate if they do282
 
 that may be the rule; if a fae lies they will suffer a horrible fate282
 
 
Fae Laws
Bargains
Mercy Thompson Series #5: Silver Borne
Traditional Structure of a Fae Bargain
Bargain is Requested
Bargain is Struck
Bargain is Accepted
Bargain is Done
 it is humans who betray their bargains
 
 accepted and sealed the bargain in blood
 
 can be a contest; usually musical; a true bargain
 
 different bargains; stories of footraces, swimming contests, eating contests
 
 fairy bargains that left you ruing the day you made them
 
 cannot break the heart of the bargain; it must be something that is possible, however unlikely—for the challenger to accomplish
 
 can be struck with other supernatural creatures; 
River Devil 
 
Mercy Thompson Series #8: Night Broken
Mercy Thompson Series #9: Fire Touched
 fae are very particular about their bargains67
 
 grandstanding is a very bad way to make bargains149
 
 few fae who can bargain for the fae as a whole166
 
 even if you bargain, you might not be safe171
 
 bargaining room; you won't know what you have until you talk to them173
 
 there is magic in bargaining with the fae that has nothing to do with what they had the power to do or not do218
 
 that's why so many of the fae are willing to strike odd bargains—they can gain power from it218
 
 a bargain can be sealed in blood220
 
 receiving an item in fulfillment of our bargain324
 
 ways to void a bargain325
 
Mercy Thompson Series #10: Silence Fallen
Mercy Thompson Series #11: Storm Cursed
Mercy Thompson Series #12: Smoke Bitten
Examples 
Thomas Hao Father bargained with Master Vampire Butte
Ariana Brewster bargained with Daphne Rondo
River Devil bargained to exchange Mercy for a child
Zee Adelbertsmiter bargained his safety for his son
Alistair Beauclaire bargained for the Walking Stick
Gray Lords bargained with Adam and Mercy to maintain neutrality in the Tri-Cities 
 
Fae Guesting Laws
Fae Policing
Mercy Thompson Series #3: Iron Kissed
 fae do their own internal policing
 
 Gray Lords own several law firms on the East Coast
 
 fae who are suspected of crimes tend not to survive to need lawyers
 
 imprisoning a fae is…impractical
 
 it's damned difficult; holding a person is hard enough; holding a fae for any time at all, if he doesn't want to be held, is near impossible
 
 a life sentence is highly impractical when fae can live for hundreds of years
 
 if you imprison fae, for whatever reason, you'd better be dead when he gets out or you'll wish you were
 
 human justice just isn't equipped to deal with the fae, so they take care of it
 
 a fae who commits a serious crime—like murder—is simply executed on the spot
 
 
Fae Magic
Fae Glamour