The Unseelie and Seelie Courts comprise the two major factions of creatures in The Feywild Although they can be thought of as rough analogues to alignment, the differences between them are not well defined for those of non-fey origin. Importantly, the distinctions are better presented in arguments of law vs. chaos than good vs. evil, although neither is quite correct. Relegating either group exclusively to these categories is a common mistake.
The lines drawn between these courts originated with a simple interpretation of a promise made by the first fey, to which all subsequent generations of fey have been bound. The promise--phrased literally--was: "Treat others as you would be treated." The long-term results of this promise, however, have reflected very little of the original intentions.
Tenets and Ideals
The Unseelie Court concern themselves mainly with perfection, privilege, and strength. They are characterized most succinctly by a warped version of "survival of the fittest" which is, in practice, more inclusive than the Seelie Court's proclivities toward beauty and purity.
The Unseelie are, by and large, welcoming of outsiders as long as they can exemplify some version of these tenets and lend their own strength to the Court when called upon. This has led to a variety of gruesome (and indeed evil) fey finding themselves among the Unseelie after having been outright rejected by the Seelie Court. It is perhaps not surprising, therefore, that they are often maligned in stories. However, there are many among the Unseelie who would be considered "good" by more common standards. It is important, therefore, not to form opinions of fey based on their court alliance alone.
The Defection of the Autumn Queen
In eons past, Sinfarena stole the sunlight from the skies over Sunhallow. In one fell swoop, this action simultaneously created the Twilight region of The Feywild and turned the Sunhallow tree--as well as the Arbor Palace palace--into stone. It is unknown exactly how or why the ancient hag accomplished this, but the legend is all the more believable by those who have since met Sinfarena and seen her eyes glow like sunsets.
The Autumn Queen was understandably furious and inconsolable, and vowed a deep and vicious revenge upon Sinfarena. It became an all-consuming obsession, but Sinfarena was extremely powerful, and made only more so by the sunlight she now possessed. The Autumn Queen turned to her regent--The Morning Queen, paragon of the Seelie Court--for assistance, but none was forthcoming. It is unknown to this day whether the help was refused, whether the request was ignored or unheard, or whether the Morning Queen simply thought it impossible.
The House Without. The offer came at a price, however, and the Autumn Queen would be required to defect to the Unseelie Court in exchange for this help. The Autumn Queen--furious with her own court and consumed by rage--agreed to the proposition. The alliance was able to bind Sinfarena, and the Autumn Queen became the only archfey in history to leave one court for another. The repercussions of this defection are still playing out in little-understood ways even today., on the other hand, offered a plan to bind Sinfarena permanently to