FadeShifters

A race of, to put it kindly, spies. Unlike NightWalkers, not all FadeShifters are necessarily spies, but by the sheer virtue of being able to be anything and anyone, they all do make excellent spies with the proper training. They had, once upon a time, a very friendly relationship with NightWalkers in that they would be contracted by NightWalkers to spy on potential targets and, in general, keep the isolated race of assassins updated on the world at large.
It remains unclear why the NightWalkers did not step in to aid their allies once the FadeShifter culture started crumbling.
FadeShifters also made excellent healers, due in part to their ability to literally become the patient and thus help patients who could not communicate as well, or who perhaps were unwilling to take direct action without seeing results.
FadeShifters, eons ago, were a primarily clan-based race with the tribal markings on their skin indicating which clan their belonged to. Within each clan was a hierarchy of leaders, caretakers, workers, and other such things. Much like ShadowWeavers, FadeShifters were inclined to raise children all together, whether the children belonged to the FadeShifters or not. A race that was neither particularly warlike nor pacifistic, FadeShifters held their own rather inscrutable morals that varied from clan to clan, though all could agree on the sanctity of children. Being able to be anything meant that FadeShifters were very good at adapting to the needs of nearly any child, whatever race they might be. Once the FadeShifters society crumbled, it appears that ShadowWeavers, another highly family-and-clan based culture, took over the general role of dumping ground for unwanted children.

The FadeShifters did not have a religion, at least not in the unifying and culture-defining way that most would identify. Several clans were known to have very high opinions on certain things, but when one can become literally anything, the impressiveness of that which might be a deity is greatly lessened. This left FadeShifters with a rather practical outlook on the world at large, granting them an easier willingness to work and adapt to other cultures. It's easy to listen to the teachings of another if it doesn't clash with your own, and if you have no teachings to follow...
As a race of inherent shapeshifters, it is known that the FadeShifters did not share the world's views on gender- in fact, from what can be pieced together, it seemed like FadeShifters by and large did not have any concept of gender whatsoever in their own society. They adapted, naturally, to the world outside, but they see virtually no difference between male and female forms and will take on whichever one is most suited to the task or, as the case may be, whichever one is more aesthetically pleasing to themselves.
The FadeShifters did have, at one point, their own language, but it was highly guarded and never revealed to outsiders- thus it is now considered extinct and there remains, in public knowledge, no written record of this language. Whether there is a clan of FadeShifters who still live in secret somewhere with possible preservations of this is a theory much bandied about by scholars, but in truth, holds no weight.
It is regrettably unclear the situations that led to the collapse of their society- was it the hunters who came for them over the centuries, particular one Willow Oaker, or was it internal strife in a people who had never gone to war before and did not know the dangers, or was it perhaps an illness, a plague much like that which struck down the Elves? Unfortunately, the collapse was long enough ago that very little knowledge remains even of FadeShifters.

In terms of abilities, it has been preserved that FadeShifters possess a unique shapeshifting ability that lets them become anything- whether or not they've even seen or encountered the creature that they are becoming. Doing so will always lead to them assuming another shape, but mastery of that shape can only come with practice. It was not uncommon to see FadeShifters preferring to stick to similar, preferred forms- perhaps different humanoids, felines, canines, draconics, etc.- but personal preferences aside, one could never predict what shape a FadeShifter might take at any given moment.
With these shapes also comes, perhaps, the most intriguing and fascinating part about the FadeShifters: their ability to duplicate, mimic, or otherwise *use* the racial abilities of others. A FadeShifter who has become an UnSeelie Faerie will most certainly be able to use magics involving ice, illusions, and perhaps to an extent, even shadows. The range of this success varies wildly from clan to clan and indeed, from FadeShifter to FadeShifter, but it is well documented that however much a FadeShifter might be able to use the abilities of another race, they will never have mastery of them. To reference the UnSeelie example above, a FadeShifter could certainly evolve the expertise to build a house of ice, but an UnSeelie Faerie would have the mastery to build a castle. Both are functional, true, but a FadeShifter's use of the power is not innate in the same way that the Faerie's would be and thus, it is lessened to an extent. That is not to say that FadeShifters cannot be dangerous in their use of others' abilities- they may never be masters, but they can certainly become stronger than the average with dedication.

This is also not to say that a FadeShifter is not dangerous in their natural form, their 'true skin' as many have taken to calling it. FadeShifters are experts in wielding magic, whether it be their own or adapted from another race, and even without Shifting can exert a measure of control over their surroundings and craft illusions that hold up nearly as well as real objects. If a FadeShifter comes at you with a sword, assume it is a real one even if you just saw them draw it from thin air- their illusions are deadly and that sword will hurt.

Then again, if you should see a FadeShifter coming at you with a sword, you would be well to beg for mercy anyway, as this would likely be the only opportunity you have to study such a fascinating race.