Here's a spitbally thought from post-midnight Fro:

In the past, when the great conflict against Turoch came to pass, there were those who did not take a side. They conferred amongst themselves regarding the conflict, their neutrality, and the choices they would have to make accordingly, and at the close of the war elected to negotiate with the victors.

The victorious party did not want the unchecked powers of Turoch's creations to be let loose on the world, nor did these neutrals wish to surrender the power they felt to be their birthright. As they worked toward a solution, rumblings of dissatisfaction and division began to grow, but ultimately the Law was struck. This Law gives the children of Turoch their full power and gifts unless they step foot among mortals, in which case their powers are limited in certain ways - defined spells and powers rather than reality-warping "soft magic," for instance, defined codes of conduct and access that govern their ability to remain in the world of mortals and still tap into their powers (for example, a demon needing to be summoned into this reality by a mortal; a fey being obliged not to touch implements of iron). The Law effectively gave the children of Turoch free rein to rule over their extraplanar fiefdoms, but vastly limited them in the realms of mortals. The fey, as the neutral party in the conflict, were the least limited...

...but they don't appreciate any limitation on their freedom.

As a result, dissatisfaction grew into division, as various factions within the fey point fingers, throw blame, and otherwise try to relitigate a closed case. The four great courts each bring a different perspective: the Earth Court was fully behind this deal and viewed it as a reasonable way for things to be settled; the Water Court wanted to use trickery and subterfuge to undermine the Law; the Air Court felt that the fey should step away from the mortal world altogether and dislikes that the Law in some way ties the fey to the world; and the Fire Court wanted to go to war to defend their total freedom to act within the world of mortals, and still seeks to overturn the Law by direct confrontation. Amongst these courts are smaller factions that vie for prominence and control.