So Fey = tricksters/pranksters?
Mm, not quite. As far as Jim Butcher is concerned:
I can't actually pull any ideas from the Seelie side, but here's a notion for the Unseelie. There's a very minor scene in "Summer Knight" where they are in a fey ballroom, where all the faeries are dancing, and there are human musicians playing. As the song winds down, a trumpet player steps out, and starts to play, and blow, and blow... his face turns purple, as he continues his solo, then his face turns black, and he falls over, dead. The Lady of Winter, a very Powerful fey, looks down at the musician the way a child might at a broken toy, smiles and says, "He wanted to give the performance of a lifetime. He gave his."
Faeries can't
lie, but getting the truth out of them is like pulling teeth. Your teeth. With a jackhammer. Dealing with the fey is like dealing with the devil. Half-truths, twisting your words against you, lies of omission, and all backing you into a perverbial corner so there's no way out but their way, and that undoubtably means your demise.
Here's another thing:
Let's say Jane the fey is on Edward's side. Bruce is Jane's lieutenant, but Bruce betrays Jane in the middle of a battle. Edward and his Friend kill Bruce in the course of that battle. Jane may then turn around and try to kill Edward's friend because Edward killed Bruce, who was on Jane's side. Even though Bruce was betraying Jane
at the time, Bruce was still under Jane's command (and thus, under her protection). Therefore, Edward took a resource from Jane, and Jane is responsible for providing protection to Bruce in principle, making Jane feel justified in getting revenge on Edward.
You ask yourself, "Why would Jane the Fey do something so petty and unnecessary?" Because Jane might be doing it out of spite, be in a bad mood, have her alliances shift, fickle, she finds it fun, to show she repays all debts and slights, it could just be in her nature, like the
Scorpion and the Frog, or all the above.
